Additions for chromadb integration

[jeffchuber]

There are few things that can be improved in the integration:

• [ ] Add tests - this will require mocking the chroma backend responses to have any value and to be a part of regular CI.
• [x] Add ability for documents to be stored in Chroma. Chroma can operate purely as a metadata-index store, but some users store documents in Chroma as well and and provide some hybrid search affordances. For example search where document $contains a string. https://github.com/chroma-core/chroma/blob/main/examples/where_filtering.ipynb