treewide: move nixos modules

modules/nixos/games/default.nix

@@ -0,0 +1,24 @@
+{ config, lib, ... }:
+
+{
+  imports = [
+    ./minecraft
+    ./mumble
+    ./particles
+    ./steam
+    ./tetris
+  ];
+
+  options.chvp.games.enable = lib.mkOption {
+    default = false;
+    example = true;
+  };
+
+  config = lib.mkIf config.chvp.games.enable {
+    chvp.games = {
+      minecraft.client = lib.mkDefault false;
+      mumble.enable = lib.mkDefault true;
+      steam.enable = lib.mkDefault true;
+    };
+  };
+}