add moonlight for game streaming

modules/nixos/gaming/default.nix

@@ -12,6 +12,7 @@
     ./legendary.nix
     ./lutris.nix
     ./minecraft-server.nix
+    ./moonlight.nix
     ./ryujinx.nix
     ./steam.nix
   ];

modules/nixos/gaming/moonlight.nix

@@ -0,0 +1,14 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+{
+
+  options.gaming.moonlight.enable = lib.mkEnableOption "Enable Moonlight game streaming client.";
+
+  config = lib.mkIf config.gaming.moonlight.enable {
+    environment.systemPackages = with pkgs; [ moonlight-qt ];
+  };
+}