HP Printer & Scanner + DWM/Polybar Dependencies

- Add packages / services to support HP printer / scanner
- Add packages to dwm that polybar modules rely on

system/hardware/printing.nix

@@ -1,8 +1,20 @@
 { config, lib, pkgs, ... }:
 
 {
+  # Printing
   services.printing.enable = true;
   services.avahi.enable = true;
   services.avahi.nssmdns4 = true;
   services.avahi.openFirewall = true;
+
+  # Scanning
+  services.saned.enable = true;
+
+  environment.systemPackages = with pkgs; [
+    # HP Printer Drivers
+    hplip
+
+    # Scanner Frontend
+    libsForQt5.skanlite
+  ];
 }