Allow retrieve collection by a collection of base ids

lib/Alchemy/Phrasea/Collection/Reference/CollectionReferenceRepository.php

@@ -29,6 +29,12 @@ interface CollectionReferenceRepository
      */
     public function find($baseId);
 
+    /**
+     * @param int[] $baseIds
+     * @return CollectionReference[]
+     */
+    public function findMany(array $baseIds);
+
     /**
      * @param int $databoxId
      * @param int $collectionId