Unbreak Debian 11 and partially Ubuntu 22.04 (Wayland+GDM+Gnome) (#81)

* Unbreaking Debian 11 and partially Ubuntu 22.04

* pre-cleanup

* pre-cleanup2

* Update im-launch

* Update gnome-extension-ding

* polishing

* not yet

* Update ubuntu.flags

Allow GDM to boot. `No new privs` fix.

* Update debian.flags

Allow GDM to boot. `No new privs` fix.

* Update CONTRIBUTING.md

* fixes

* reverting w

* move setpriv to main.flags

apparmor.d/groups/freedesktop/xwayland

@@ -31,8 +31,11 @@ profile xwayland @{exec_path} flags=(attach_disconnected) {
   /usr/share/fonts/X11/{,**} r,
   /usr/share/X11/xkb/rules/evdev r,
 
+  owner /var/lib/gdm{3,}/.cache/mesa_shader_cache/index rw,
+
   owner /tmp/server-[0-9]*.xkm rwk,
   owner @{run}/user/@{uid}/.mutter-Xwaylandauth.[a-zA-z0-9]* rw,
+  owner @{run}/user/@{uid}/xwayland-shared-?????? rw,
 
   @{sys}/bus/pci/devices/ r,
   @{sys}/devices/system/cpu/possible r,