kodi: Use Gamescope as wayland compositor

[JGoutin]

Gamescope may be a good alternative to sway, because more lightweight, have useful features (HDR ?), and does not require extra files just a simple command in the SystemD:
ExecStart=/usr/bin/gamescope -- /usr/bin/kodi-standalone

Possible useful arguments (to add before --):
--adaptive-sync, --expose-wayland, --hdr-enabled

REF: https://github.com/ValveSoftware/gamescope/blob/master/src/main.cpp

Note: Current version available on Fedora don't support --expose-wayland and is detected as X11 display by Kodi, maybe this can lead to issues.