nixos/netbox: increase timeout for NetBox pre-start script

since the script does database migrations and index,
it could timeout on slower system with a big enough database

nixos/modules/services/web-apps/netbox.nix

@@ -324,6 +324,7 @@ in {
               --pythonpath ${pkg}/opt/netbox/netbox
           '';
           PrivateTmp = true;
+          TimeoutStartSec = lib.mkDefault "5min";
         };
       };