feat: introduce specialisations into nix config

hosts/common/optional/gaming.nix

@@ -1,16 +0,0 @@
-{ pkgs, ... }:
-
-{
-  programs = {
-    steam = {
-      enable = true;
-      gamescopeSession.enable = true;
-    };
-
-    # to run steam games in game mode, add the following to the game's properties from within steam
-    # gamemoderun %command%
-    gamemode.enable = true;
-  };
-
-  environment.systemPackages = with pkgs; [ mangohud protonup-qt ];
-}

hosts/common/specialisations/gaming.nix

@@ -0,0 +1,20 @@
+{ pkgs, ... }:
+
+{
+  specialisation.gaming.configuration = {
+    programs = {
+      steam = {
+        enable = true;
+        gamescopeSession.enable = true;
+      };
+
+      # to run steam games in game mode, add the following to the game's properties from within steam
+      # gamemoderun %command%
+      gamemode.enable = true;
+    };
+
+    powerManagement.cpuFreqGovernor = "performance";
+
+    environment.systemPackages = with pkgs; [ mangohud protonup-qt ];
+  };
+}

hosts/common/specialisations/powersave.nix

@@ -0,0 +1,7 @@
+{ ... }: 
+
+{
+  specialisation.powersave.configuration = {
+    powerManagement.cpuFreqGovernor = "powersave";
+  };
+}