Add GNOME

- Add config option to switch between window managers / desktop environments
- Remove systemPackages attribute when a service or program attribute is available
- Add GNOME to gui

flake.nix

@@ -25,6 +25,7 @@
         timezone = "America/New_York";         # Time Zone
         locale = "en_US.UTF-8";                # Locale
         diskoConfig = "luks-btrfs-subvolumes"; # Select the disko config that was used to partition drive
+        desktopEnvironment = "gnome";          # Window Manager / Desktop Environment to use
       };
 
       # --- USER SETTINGS --- #