Refactor the whole configuration

Reviewed-on: #1

modules/nixos/multimedia/games/default.nix

@@ -0,0 +1,21 @@
+{ pkgs, username, ... }:
+
+{
+  environment.persistence."/nix/persist" = {
+    users."${username}".directories = [
+      ".local/share/steam_home"
+      ".local/share/osu"
+    ];
+  };
+
+  environment.systemPackages = with pkgs; [
+    protonup-qt
+    protontricks
+    unstable.osu-lazer-bin
+  ];
+
+  programs.steam = {
+    enable = true;
+    gamescopeSession.enable = true;
+  };
+}