feat:Add vector type and vector factory class for vector database integration

backend/open_webui/routers/retrieval.py

@@ -36,7 +36,7 @@ from open_webui.models.knowledge import Knowledges
 from open_webui.storage.provider import Storage
 
 
-from open_webui.retrieval.vector.connector import VECTOR_DB_CLIENT
+from open_webui.retrieval.vector.factory import VECTOR_DB_CLIENT
 
 # Document loaders
 from open_webui.retrieval.loaders.main import Loader