Explore Improving Namespace UX

[collindutter]

• I have read and agree to the contributing guidelines.

Is your feature request related to a problem? Please describe.
Vector Store Drivers require a namespace field when upserting and querying. There are a few issues with this:

• Not all Vector Stores have the concept of a namespace. This means that each Vector Store Driver interprets and implements namespaces in slightly different ways. For instance: PineconeVectorStoreDriver uses Pinecone namespaces while QdrantVectorStoreDriver seemingly doesn't use it at all (TIL??).
• It is easy for users to shoot themselves in the foot by unknowingly upserting documents in a namespace and then querying a different one, yielding no entries.

Describe the solution you'd like
I'd like to take another pass over Vector Store Drivers and evaluate the use of namespaces to see if there are improvements we can make.

Additional context

• Example of foot shooting Fix vector store driver docs #1508