Change structure, add scanner deps and fix configurations

modules/system/nixos/networks/printing.nix

@@ -1,4 +1,5 @@
 {
+  pkgs,
   lib,
   config,
   ...
@@ -6,6 +7,8 @@
 with lib;
 let
   cfg = config.os.networks.printing;
+  all = builtins.attrNames config.users.users;
+  users = builtins.filter (user: config.users.users.${user}.isNormalUser == true) all;
 in
 {
   options.os.networks.printing = {
@@ -15,7 +18,17 @@ in
 
     services.printing = {
       enable = true;
+      startWhenNeeded = true;
+      drivers = with pkgs; [ hplip ];
     };
 
+    hardware.sane = {
+      enable = true;
+      extraBackends = with pkgs; [ sane-airscan ];
+    };
+
+    users.groups.lp.members = users;
+    users.groups.scanner.members = users;
+
   };
 }