WIP: main/postmarketos-ui-kodi: switch to KMS from Wayland

This allows changing resolution, refresh rate, and more settings from within Kodi itself by skipping the compositor completely. It is launched via a service script which runs it as it's own dedicated user. The system can now also be shutdown or rebooted from within Kodi itself.

I have problems with this in Qemu however. Before I completed the MR I was able to control the instance with my keyboard, which I now can't. I can still control it fine with my mouse though, so input in general isn't the problem. It also works fine on my laptop running bare Alpine Linux, so I'm not sure what's up. Will need testing on a real device.