Backport GNOME 42 dark/light switcher & high contrast handling
We would like to backport the new GNOME 42 theme stuff to Ubuntu 22.04 LTS.
- GNOME/gnome-control-center@ecd6124b
- GNOME/gnome-control-center@f89976ff
- GNOME/gnome-control-center@c1f8e936
- And also enable gnome-control-center itself to support the dark/light switcher (GNOME got this automatically because they are using libadwaita but we need to use libhandy to opt in)