The current MEVD connectors contains both the new IVectorStore implementations and the legacy IMemoryStore implementations; the latter are legacy at this point, and users should be moving away from them to the new IVectorStore implementations.

We need to finalize the exact plan here, but we should start by obsoleting all IMemoryStore-related APIs to signal to users to move to IVectorStore; the obsoletion message would ideally point to a migration guide, a cutoff date, etc.