Reintroduce the concept of pagination of the semantic search

Thanks to the incorporation of Milvus Group search into our application, we are capable of correctly implementing search result offset.
- The only situation where the pages could overlap or the results could be mismatched in general is if the database is updated in the meantime...
- The main blocker (working with chunk embeddings rather than document embedding) is resolved thanks to the Group search

BLOCKERS:
- [ ] Discuss with others whether we wish to implement this. The feature should take less than an hour...