This pull request addresses the need to share a single `chromadb.Client`
instance across multiple instances of the `Chroma` class. By
implementing a shared client, we can maintain consistency and reduce
resource usage when multiple instances of the `Chroma` classes are
created. This is especially relevant in a web app, where having multiple
`Chroma` instances with a `persist_directory` leads to these clients not
being synced.
This PR implements this option while keeping the rest of the
architecture unchanged.
**Changes:**
1. Add a client attribute to the `Chroma` class to store the shared
`chromadb.Client` instance.
2. Modify the `from_documents` method to accept an optional client
parameter.
3. Update the `from_documents` method to use the shared client if
provided or create a new client if not provided.
Let me know if anything needs to be modified - thanks again for your
work on this incredible repo