glade: use margin_start/margin_end instead of left/right

The latter is deprecated in favor of the former. The difference in
behavior is that they have opposite meanings in RTL scripts, which is
probaby good (well, at least for the labels).

Notably, this future-proofs us for Gtk4 that drops the deprecated
properties.

src/connection-editor/ce-page-ethernet.ui

@@ -254,7 +254,7 @@
             <property name="visible">True</property>
             <property name="can_focus">True</property>
             <property name="receives_default">False</property>
-            <property name="margin_right">12</property>
+            <property name="margin_end">12</property>
             <property name="use_underline">True</property>
             <property name="xalign">0</property>
             <property name="draw_indicator">True</property>
@@ -270,7 +270,7 @@
             <property name="visible">True</property>
             <property name="can_focus">True</property>
             <property name="receives_default">False</property>
-            <property name="margin_right">12</property>
+            <property name="margin_end">12</property>
             <property name="use_underline">True</property>
             <property name="xalign">0</property>
             <property name="draw_indicator">True</property>
@@ -439,7 +439,7 @@
       <object class="GtkLabel" id="ethernet_speed_label">
         <property name="visible">True</property>
         <property name="can_focus">False</property>
-        <property name="margin_left">26</property>
+        <property name="margin_start">26</property>
         <property name="label" translatable="yes">_Speed</property>
         <property name="use_underline">True</property>
         <property name="mnemonic_widget">ethernet_speed</property>
@@ -473,7 +473,7 @@
       <object class="GtkLabel" id="ethernet_duplex_label">
         <property name="visible">True</property>
         <property name="can_focus">False</property>
-        <property name="margin_left">26</property>
+        <property name="margin_start">26</property>
         <property name="label" translatable="yes">Duple_x</property>
         <property name="use_underline">True</property>
         <property name="mnemonic_widget">ethernet_duplex</property>

src/connection-editor/ce-page-team-port.ui

@@ -155,8 +155,8 @@
         <child internal-child="action_area">
           <object class="GtkButtonBox" id="advanced_buttons">
             <property name="can_focus">False</property>
-            <property name="margin_left">6</property>
-            <property name="margin_right">6</property>
+            <property name="margin_start">6</property>
+            <property name="margin_end">6</property>
             <property name="margin_top">6</property>
             <property name="margin_bottom">6</property>
             <property name="layout_style">end</property>
@@ -199,8 +199,8 @@
           <object class="GtkNotebook" id="advanced_notebook">
             <property name="visible">True</property>
             <property name="can_focus">True</property>
-            <property name="margin_left">6</property>
-            <property name="margin_right">6</property>
+            <property name="margin_start">6</property>
+            <property name="margin_end">6</property>
             <property name="margin_top">6</property>
             <property name="margin_bottom">6</property>
             <child>

src/connection-editor/ce-page-team.ui

@@ -531,8 +531,8 @@
         <child internal-child="action_area">
           <object class="GtkButtonBox" id="advanced_buttons">
             <property name="can_focus">False</property>
-            <property name="margin_left">6</property>
-            <property name="margin_right">6</property>
+            <property name="margin_start">6</property>
+            <property name="margin_end">6</property>
             <property name="margin_top">6</property>
             <property name="margin_bottom">6</property>
             <property name="layout_style">end</property>
@@ -575,8 +575,8 @@
           <object class="GtkNotebook" id="advanced_notebook">
             <property name="visible">True</property>
             <property name="can_focus">True</property>
-            <property name="margin_left">6</property>
-            <property name="margin_right">6</property>
+            <property name="margin_start">6</property>
+            <property name="margin_end">6</property>
             <property name="margin_top">6</property>
             <property name="margin_bottom">6</property>
             <child>

src/libnma/nma-mobile-wizard.ui

@@ -95,7 +95,7 @@
           <object class="GtkLabel" id="provider_name_label">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
-            <property name="margin_left">25</property>
+            <property name="margin_start">25</property>
             <property name="label" translatable="yes">Your broadband provider’s name</property>
             <property name="xalign">0</property>
           </object>
@@ -109,7 +109,7 @@
           <object class="GtkLabel" id="plan_name_label">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
-            <property name="margin_left">25</property>
+            <property name="margin_start">25</property>
             <property name="label" translatable="yes">Your broadband billing plan name</property>
             <property name="xalign">0</property>
           </object>
@@ -123,7 +123,7 @@
           <object class="GtkLabel" id="apn_label">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
-            <property name="margin_left">25</property>
+            <property name="margin_start">25</property>
             <property name="label" translatable="yes">(in some cases) Your broadband billing plan APN (Access Point Name)</property>
             <property name="xalign">0</property>
           </object>
@@ -254,7 +254,7 @@
             <property name="height_request">140</property>
             <property name="visible">True</property>
             <property name="can_focus">True</property>
-            <property name="margin_left">25</property>
+            <property name="margin_start">25</property>
             <property name="vexpand">True</property>
             <property name="hscrollbar_policy">never</property>
             <property name="shadow_type">in</property>
@@ -296,7 +296,7 @@
           <object class="GtkGrid">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
-            <property name="margin_left">25</property>
+            <property name="margin_start">25</property>
             <property name="row_spacing">12</property>
             <property name="column_spacing">12</property>
             <child>
@@ -505,7 +505,7 @@ If you are unsure of your plan please ask your provider for your plan’s APN.</
           <object class="GtkLabel" id="confirm_device">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
-            <property name="margin_left">25</property>
+            <property name="margin_start">25</property>
             <property name="xalign">0</property>
           </object>
           <packing>
@@ -531,7 +531,7 @@ If you are unsure of your plan please ask your provider for your plan’s APN.</
           <object class="GtkLabel" id="confirm_provider">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
-            <property name="margin_left">25</property>
+            <property name="margin_start">25</property>
             <property name="xalign">0</property>
           </object>
           <packing>
@@ -562,7 +562,7 @@ If you are unsure of your plan please ask your provider for your plan’s APN.</
               <object class="GtkLabel" id="confirm_plan">
                 <property name="visible">True</property>
                 <property name="can_focus">False</property>
-                <property name="margin_left">25</property>
+                <property name="margin_start">25</property>
                 <property name="xalign">0</property>
               </object>
               <packing>
@@ -575,7 +575,7 @@ If you are unsure of your plan please ask your provider for your plan’s APN.</
               <object class="GtkLabel" id="confirm_apn">
                 <property name="visible">True</property>
                 <property name="can_focus">False</property>
-                <property name="margin_left">25</property>
+                <property name="margin_start">25</property>
                 <property name="ypad">6</property>
                 <property name="xalign">0</property>
               </object>

src/libnma/nma-pkcs11-token-login-dialog.ui

@@ -56,8 +56,8 @@
           <object class="GtkBox">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
-            <property name="margin_left">12</property>
-            <property name="margin_right">12</property>
+            <property name="margin_start">12</property>
+            <property name="margin_end">12</property>
             <property name="margin_top">12</property>
             <property name="margin_bottom">12</property>
             <property name="orientation">vertical</property>

src/libnma/nma-vpn-password-dialog.ui

@@ -62,8 +62,8 @@
           <object class="GtkGrid">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
-            <property name="margin_left">12</property>
-            <property name="margin_right">12</property>
+            <property name="margin_start">12</property>
+            <property name="margin_end">12</property>
             <property name="margin_top">12</property>
             <property name="margin_bottom">12</property>
             <property name="row_spacing">6</property>
@@ -185,8 +185,8 @@
               <object class="GtkImage">
                 <property name="visible">True</property>
                 <property name="can_focus">False</property>
-                <property name="margin_left">6</property>
-                <property name="margin_right">12</property>
+                <property name="margin_start">6</property>
+                <property name="margin_end">12</property>
                 <property name="margin_top">6</property>
                 <property name="margin_bottom">6</property>
                 <property name="yalign">0</property>