Floating windows, UI implementation, and compositor improvements for the new COSMIC desktop environment.

cross-posted from: https://discuss.tchncs.de/post/6777822

Notable changes:

  • Tracking improvements. For example, if you use the launcher to launch an application and then switch workspaces, it will still launch in the workspace you opened it from;
  • Supported the ext-session-lock protocol, which authenticates the user and informs the compositor when the session should be unlocked
  • XDG activation and DBus activation support
  • work on HDR
  • Ongoing work to package COSMIC on NixOS: tracking issue