nixos/networking: add the wakeonlan option

nixos/modules/tasks/network-interfaces-scripted.nix

@@ -61,6 +61,8 @@ let
           MACAddress = i.macAddress;
         } // optionalAttrs (i.mtu != null) {
           MTUBytes = toString i.mtu;
+        } // optionalAttrs (i.wakeOnLan.enable == true) {
+          WakeOnLan = "magic";
         };
       };
     in listToAttrs (map createNetworkLink interfaces);