implement multi relation loading

src/Interfaces/PersistentData/IPersistentDataManager.php

@@ -16,6 +16,8 @@ interface IPersistentDataManager
 
     public function loadRelationsFromDb(Model $model, bool $recursive = false, array $withRelations = []): void;
 
+    public function loadMultiRelationsFromDb(array $models, string $relation, bool $useRelations = false, array $withRelations = []): void;
+
     public function saveToDb(Model $model): void;
 
     public function deleteFromDb(Model $model): void;