Remove elasticsearch as mandatory dependency (#585)

embedchain/__init__.py

@@ -6,7 +6,5 @@ from embedchain.apps.App import App  # noqa: F401
 from embedchain.apps.CustomApp import CustomApp  # noqa: F401
 from embedchain.apps.Llama2App import Llama2App  # noqa: F401
 from embedchain.apps.OpenSourceApp import OpenSourceApp  # noqa: F401
-from embedchain.apps.PersonApp import (PersonApp,  # noqa: F401
-                                       PersonOpenSourceApp)
+from embedchain.apps.PersonApp import PersonApp, PersonOpenSourceApp  # noqa: F401
 from embedchain.vectordb.chroma_db import ChromaDB  # noqa: F401
-from embedchain.vectordb.elasticsearch_db import ElasticsearchDB  # noqa: F401