feat: Faiss and In memory store

[HaoXuAI]

What this PR does / why we need it:

Which issue(s) this PR fixes:

Misc

[HaoXuAI]

@franciscojavierarceo @tokoko an tentative implementation for faiss + inmemory db for vector store

[dmartinol]

Hey, I just integrated this change to raise a new PR and the linter failed:

feast/infra/online_stores/contrib/faiss_online_store.py:173: error: Return type "list[tuple[datetime | None, Value | None, Value | None, Value | None]]" of "retrieve_online_documents" incompatible with return type "list[tuple[datetime | None, EntityKey | None, Value | None, Value | None, Value | None]]" in supertype "OnlineStore"  [override]

Its return type:

    ) -> List[
        Tuple[
            Optional[datetime],
            Optional[Value],
            Optional[Value],
            Optional[Value],
        ]
    ]:

does not match the supertype signature:

    ) -> List[
        Tuple[
            Optional[datetime],
            Optional[EntityKeyProto],
            Optional[ValueProto],
            Optional[ValueProto],
            Optional[ValueProto],
        ]
    ]:

Can you pls take a look? @HaoXuAI @franciscojavierarceo

[franciscojavierarceo]

Just to close this thread, I fixed this.