universedesktop: Migrate to desktop config to dedicated directory

machines/universedesktop/desktop/default.nix

@@ -0,0 +1,31 @@
+{ config, pkgs, lib, ... }: {
+  # Wayland support
+  hardware = {
+    opengl.enable = true;
+    opengl.driSupport = true;
+    opengl.driSupport32Bit = true;
+
+    nvidia = {
+      modesetting.enable = true;
+      powerManagement.enable = true;
+      open = false;
+    };
+  };
+  services.xserver.enable = true;
+  services.displayManager.sddm.enable = true;
+  services.xserver.desktopManager.plasma5.enable = true;
+  programs.xwayland.enable = true;
+  # Configure keymap in X11
+  services.xserver.xkb.layout = "us";
+  # Enable sound.
+  # rtkit is optional but recommended
+  security.rtkit.enable = true;
+  services.pipewire = {
+    enable = true;
+    alsa.enable = true;
+    alsa.support32Bit = true;
+    pulse.enable = true;
+    # If you want to use JACK applications, uncomment this
+    # jack.enable = true;
+  };
+}