v1.1: Perform multiple searches in a single query

[maryamsulemani97]

With v1.1, Meilisearch will perform multiple search queries on one or more indexes by bundling them into a single request.

To do

• Document new multi-search route
• Update quick start
• Update _redirects file

References

• Issue on core: Perform multiple searches in a single query meilisearch#3427
• Spec: Multi Search API specifications#225
• Notion: https://www.notion.so/meilisearch/Support-multi-requests-at-search-f1b177a999ff43db9bb9af615cb346ca?pvs=4
• SME: @dureuill