feat: Cohere and OpenAI rerankers for QA retrieval

[makseq]

See more info in the tutorial: https://labelstud.io/blog/improving-rag-document-search-quality-with-cohere-re-ranking/#integrate-label-studio-with-the-qa-system

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 51.14%. Comparing base (d244898) to head (2582a92). Report is 12 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #467      +/-   ##
==========================================
+ Coverage   51.11%   51.14%   +0.03%     
==========================================
  Files          38       40       +2     
  Lines        2477     2716     +239     
==========================================
+ Hits         1266     1389     +123     
- Misses       1211     1327     +116     

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.