Add support for the system76 launch keyboard configurator.

nix/configuration/configuration.nix

@@ -28,6 +28,7 @@
     ./roles/graphics
     ./roles/sound
     ./roles/sway
+    ./roles/kanshi
     ./roles/alacritty
     ./roles/firefox
     ./roles/chromium
@@ -47,6 +48,7 @@
     ./roles/media
     ./roles/steam
     ./roles/latex
+    ./roles/launch_keyboard
   ];
 
   nix.settings.experimental-features = [