Refactor RetrieveChat

[thinkall]

Why are these changes needed?

Refactor RetrieveChat to unify vector db related APIs and make it easier to plug in new vector dbs.

This PR is based off PR #619. We merged PR #619 into the branch "refactor_rag" instead of "main" because @AyushExel doesn't have time to continue working on it, and there are still some issues that need to be resolved in that PR.

Related issue number

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[hsm207]

@thinkall is there a target date to resolve the remaining issues in PR #619 ?

[thinkall]

@thinkall is there a target date to resolve the remaining issues in PR #619 ?

#619 is closed. There is no target date for this refactor PR as it's now holiday days and I'll be oof in the next month. I suggest you follow the current docs to integrate weaviate db. Sorry for the inconvenience.

[thinkall]

Check out #1727