add paginator in boxes and deliveries

lib/domain/constants.dart

@@ -11,6 +11,7 @@ const cargo_types_collection = "cargo_types";
 const custom_duties_collection = "custom_duties";
 const discounts_by_weights_collection = "discounts_by_weight";
 const shipments_collection = "shipments";
+const boxes_collection = "boxes";
 
 // docs
 const setting_doc_id = "setting";