Reduce minimum application width to fit in narrow screens
This allows to fit the application in narrower screens like phones, where the app would already fit before GTK4 transition.
Closes #237 (closed)
Going a bit more into detail, the current minimum width the application can use is 388px. Narrow screens of phones have often narrower widths (e.g: PinePhone with Phosh works usually at 360px: 720px width and 200% scale). GNOME contacts 41 was able to reach such widths, but the redesign in GNOME contacts 42, although looks much, much nicer, can only reach 388px.
This MR is an attempt to fix the problem by applying small UI changes which let the application fit smaller widths. Also, I am not a designer and I lack the ability to see whether something is a good design or not. However, I hope that the multiple solutions presented here are a step in the right direction and some iterations can help reach a design that fits all the needs :)
To start, this MR contains two commits. Both of them by themselves allow widths narrower than 360px to be reached. I present them here so that there are already multiple alternatives for the maintainers to choose from and discuss, although they could already be both applied.
Some screenshots and their minimum widths. Please note that they were taken in a laptop, so that they are completely visible:
Original screenshots, minimum width: 388px
Commit "data/ui/style: reduce margin of contact list" applied, minimum width: 352px
I have reduced the vertical and horizontal margins proportionally, but that is certainly not a requirement.
Commit "Reduce the size of big icons" applied, minimum width: 356px
Both commits applied, minimum width: 320px
