Add metadata filtering to QueryPinecone

The QueryPinecone processor should be improved to allow for metadata filtering.

https://docs.pinecone.io/docs/metadata-filtering

https://medium.com/@gmarcilhacy/deep-dive-into-langchain-and-pinecone-metadata-filtering-75a9b6eba9c

An optional filter property should be added to the processor allowing a user to specify which metadata filters should be applied to the query.