move nvidia.nix to hardware folder

hardware/nvidia.nix

@@ -0,0 +1,24 @@
+# configure nvidia graphics drivers
+# see https://nixos.wiki/wiki/Nvidia
+
+{ config, lib, pkgs, ... }:
+{
+  hardware.graphics.enable = true;
+
+  services.xserver.videoDrivers = ["nvidia"];
+
+  hardware.nvidia = {
+    modesetting.enable = true;
+
+    powerManagement.enable = false;
+    powerManagement.finegrained = false;
+
+    # open-source kernel modules
+    open = true;
+
+    nvidiaSettings = true;
+
+    # set specific version
+    package = config.boot.kernelPackages.nvidiaPackages.latest;
+  };
+}