Added Brightnessctl kernel params

hosts/hp15-n028sg/default.nix

@@ -23,7 +23,12 @@
     ./hardware-configuration.nix
   ];
 
+  # Brightness Control
+  # Enabled and Kernel patched to control screen Brightness on Notebook
   environment.systemPackages = with pkgs; [ brightnessctl ];
+  services.udev.extraRules = ''
+    		ACTION=="add", SUBSYSTEM=="backlight", KERNEL=="*", RUN+="${pkgs.coreutils}/bin/chmod a+w /sys/class/backlight/%k/brightness"
+    	'';
 
   boot.loader = {
     systemd-boot.enable = true;