docs: Add documentation for Hybrid Search

[dishaprakash]

Adds documentation for hybrid search

This PR adds:

• A code snippet in the README
• Section in the how-to guide on multiple scenarios the hybrid search config can be used in. The scenarios are
  - Creating a new table with the tsv column
  - Using a pre-existing table without the tsv column
  - Hybrid search only on specific similarity searches.
  - Applying hybrid search index

[averikitsch]

How are we selecting what metadata column is being used in the hybrid search?