ui: Add Shortcuts to the application menu

https://gitlab.gnome.org/GNOME/gnome-games/issues/39
4 jobs for wip/aplazas/app-menu in 20 minutes and 39 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build
passed flatpak:app #52448

00:14:39

 
  Test
passed flatpak:tests #52449

00:05:15

 
  Review
passed review #52450

00:00:21

passed stop_review #52451
manual

00:00:23