sync with gtk:adwaita for 3.32
There's been a number of changes in adwaita. Once the dust settles we need to fold those changes back to the shell.
Color updates (primary color scheme is Adwaita:light, overview is toned down (osd style). Prepare for easy Adwaita:dark opt in.)
New switch design
New rounded menubars, popovers (5x border-raidus as opposed to 3)