flakes: Migrate the config and miku to flakes

modules/services/gamemode/default.nix

@@ -0,0 +1,29 @@
+{ config, lib, ... }:
+
+let
+  cfg = config.ptw.services.gamemode;
+in {
+  options.ptw.services.gamemode = {
+    enable = lib.mkEnableOption "Enable and configure gamemode";
+  };
+
+  config = lib.mkIf cfg.enable {
+    programs.gamemode = {
+      enable = true;
+      enableRenice = true;
+      settings = {
+        general = {
+          reaper_freq = 5;
+          desiredgov = "performance";
+          igpu_desiredgov = "powersave";
+          igpu_power_threshold = 0.3;
+
+          softrealtime = "on";
+          renice = 0;
+          ioprio = 0;
+          inhibit_screensaver = 1;
+        };
+      };
+    };
+  };
+}