[KM-512] add Pydantic model the LLM fills via function calling in sql_query, and add same signature for db and tabular

[KM-438][KM-439] framework for knowledge retriever

[NOTICKET][DB] pisahin db credential ke folder model. add ingestion endpoint at db_client to use db pipeline. add router db_client di main.

[KM-467] [DED][AI] Orchestration Agent - Init