Draft: Add new gtkwaylandsink element
From the main commit:
This is based on gtksink, but similar to waylandsink uses Wayland APIs directly instead of rendering with Gtk/Cairo primitives.
In preparation for that, move reusable parts out of waylandsink into a library. If preferred, this can be split out into its own MR.
- Weston: ✓
broken resize, needs https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2232✓ fixed in 42/41.4/40.9
pattern is stuck on first frame, see https://bugs.kde.org/show_bug.cgi?id=448470✓(?) fixed in 5.24/ 5.23.?
- Sway: heavy glitches on stable, minor ones on master, see https://github.com/swaywm/sway/issues/6763