xkb: disable compose and unbind alt char key as best as I can

This was messing with me in UFO 50, since I used Right-Alt and
Right-Control for the second player's inputs. This functionally gets rid
of the alternate character and compose binds, so I can bind those keys
normally.

base/features/xkb.nix

@@ -25,7 +25,7 @@ in
     xkb-options =
     [
       "terminate:ctrl_alt_bksp"
-      "compose:rctrl" # Right control --> weird characters
+      "lv3:rwin_switch"
     ];
     sources = lib.singleton # Override gnome to use our custom layout, required
     (