Support a Pinecone backing store

[jkomoros]

The "library.json loaded up in memory" is fine for small libraries and as a quickstart, but a backing store like Pinecone is useful for large libraries and performance.

Creating a tracking issue to associate commits with for future reference.

68940159a62b3d0f2e1fc57a4d684c29fd999e89 and 69a48c3c00c68e09c9763c53d106a762035d96df are related.