[Feature] datastore support for Cassandra

[phact]

Hello Folks,

Thanks for creating and maintaining this great project. I'm excited to submit this PR to add datastore support for Apache Cassandra

The code includes:

• upserting embedings and metadata into a cassandra table indexed with SAI (the embedding uses the brand new c* vector<float, n> type and index)
• querying by cosine similarity and metadata (including score using cql similarity function)
• point deletes and truncate
• readme / docs
• unit tests
• support for secure connect bundle for AstraDB

I will be actively maintaining this on behalf of DataStax

[phact]

@alexleventer @msmygit I think all your comments are resolved. Thanks for the reviews!

[phact]

@isafulf would you mind having a look and helping us get this merged?

Thanks in advanced! Please let me know if I'm pinging the wrong person.

[phact]

@isafulf @luquitared we're hoping for a review. Thanks again!

[phact]

Hi @isafulf, could you please review?

[tjake]

👋 although this is going into Cassandra it’s not yet released. So this is really about supporting vector search in AstraDB which is released and being used in production. I’d appreciate it if this PR can be reviewed by a CodeOwner. Let me know if there’s any way I can help!

[phact]

Merged conflicts introduced in https://github.com/openai/chatgpt-retrieval-plugin/commit/e8fda700edd6f5bc5e6e4f57b7aa163a8adb11be

[phact]

@isafulf checking in once more

[msmygit]

@isafulf could you take a look at this PR which is pending merge for sometime now? This is now used by many enterprises already and having this would be handy. Thank you in advance!