Change searchbar in overview to show at full height

Created by: willmac321

I noticed when the panel is set to autohide in the overview, the search bar in gnome for arch/manjaro would be squished since the margin was being set.

Changing this to use padding instead allows everything to line up and display at the proper height.

Also put in separators into the menu and a toggle for the margin vs padding for search since some folks may want to have control of that feature.

• default to setting padding on search bar in overview
• since setting the top margin squished the search bar in gnome as used by arch/manjaro,
  • added a toggle for to use margin/padding so that either can be used in case a different flavor of linux has a slightly different layout

with margin in arch

with padding in arch

menu toggle add and seperators