Separate System and User packages

- Move user programs out of systems section and int
  user section
- Install user packages with home manager rather than
  system wide

user/gaming/utilities.nix

@@ -0,0 +1,15 @@
+{ config, lib, pkgs, ... }:
+
+{
+  programs.gamemode = {
+    enable = true;
+    # settings = {};
+    # enableRenice = true;
+  };
+
+  home.packages = (with pkgs; [
+    mangohud
+    goverlay
+    vkbasalt
+  ]);
+}