Add nvidia-disable profile

This is already used in XPS 15-9560, but instead of defining it in XPS
15-9560 let's create a separate profile and expose it for those who want
to disable their NVIDIA GPU.

common/gpu/nvidia-disable.nix

@@ -0,0 +1,10 @@
+{ lib, pkgs, ... }:
+
+{
+  # This runs only Intel and nvidia does not drain power.
+
+  ##### disable nvidia, very nice battery life.
+  hardware.nvidiaOptimus.disable = lib.mkDefault true;
+  boot.blacklistedKernelModules = lib.mkDefault [ "nouveau" "nvidia" ];
+  services.xserver.videoDrivers = lib.mkDefault [ "intel" ];
+}