Services, refactor, clean up, service to automatic

Move service to automatic since it has a separate purpose.

Refactor the default.nix code to include service.nix files so it is
easier to extend code.

nixosModules/services/nvidia/service.nix

@@ -0,0 +1,31 @@
+{ config, pkgs, lib, ... }:
+
+{
+  options.nvidia = {
+    enable = lib.mkEnableOption
+      "Enables nvidia with proprietary drivers";
+  };
+
+  config = lib.mkIf config.nvidia.enable {
+    hardware.graphics = {
+      enable = true;
+      extraPackages = with pkgs; [
+        rocm-opencl-icd
+        rocm-opencl-runtime
+      ];
+    };
+
+    services.xserver.videoDrivers = ["nvidia"];
+
+    hardware.nvidia = {
+      modesetting.enable = true;
+      package = config.boot.kernelPackages.nvidiaPackages.beta;
+    };
+
+    boot.kernelParams = [ "nvidia_drm.fbdev=1" ];
+
+    environment.systemPackages = with pkgs; [
+      nvidia-vaapi-driver
+    ];
+  };
+}