added steam + other gaming support

specifically applied to laptop only currently

hosts/modules/steam.nix

@@ -11,14 +11,26 @@
       "steam-run"
     ];
 
-  programs.steam = {
-    enable = true;
-    remotePlay.openFirewall = true;
-    dedicatedServer.openFirewall = true;
-    localNetworkGameTransfers.openFirewall = true;
+  programs = {
+    steam = {
+      enable = true;
+      gamescopeSession.enable = true;
+
+      remotePlay.openFirewall = true;
+      dedicatedServer.openFirewall = true;
+      localNetworkGameTransfers.openFirewall = true;
+    };
+
+    gamemode.enable = true;
   };
 
   environment.systemPackages = with pkgs; [
     steamcmd
+
+    mangohud
+    protonup-qt
+    lutris
+    bottles
+    heroic
   ];
 }