RAG: apply auto-cut off ranked retrievals

[MrCsabaToth]

Weaviate applies a technique called auto-cut. That's when there's a noticeable drop happens as we walk along the scores of the retrievals in reverse order fashion. When that drop happens it's better to drop all the rest of the retrievals. See:

• Blog post: https://weaviate.io/blog/advanced-rag#1-autocut-to-remove-irrelevant-information
• Slide deck: https://docs.google.com/presentation/d/128ZeqnKpHi1WY4-ONQNmtYewFw6LXOiNzsUWNRbssPI/edit?_hsenc=p2ANqtz-_zuQC_sdv6o1LCc5taohaU2SuTgCTRqdMI91Z6VfQMTpL1FoV_LH84MS90S4w_GuZILMPQoXhXVtLvcEP9qSFmv-8gAeONs5cxHvpvU11FH4QxVQI&_hsmi=318722944#slide=id.g279de5992e9_0_956
• Slide deck PDF export: LinkedInWkShopAdRAG.pdf