Vectorstore interface is too small

[KaymeKaydex]

There is no way to:

• Find and delete somthing by ID
• Use another namespace without new connection

[JasonHonKL]

Same thought here. Please support faiss db.

[SudoBrendan]

I would find value in adding deletion functions to the interface. It looks like at least some vectorstores support this already, but if it's not in the interface, I can't trust it as much to build my tools off of.