[nix] moves gaming stuff to it's own file.

flake.nix

@@ -27,7 +27,7 @@
     };
   };
 
-  outputs = { self, nixpkgs, ... }@inputs: 
+  outputs = { self, nixpkgs, ... }@inputs: {
     nixosConfigurations = {
       drew-desktop = (import ./system/hosts/drew-desktop) {
         inherit inputs;