[v1.11.0] Support facet distribution for federated search

[curquiza]

Related to meilisearch/integration-guides#303

Explanation of the feature

• Request facet distributions and facet stats in your federated search, by using federation.facetsByIndex in the POST /multi-search route.
• Merge the returned facets in a single facet distribution and stats that is global to the entire request, by using federation.mergeFacets in the POST /multi-search route.

Usage: https://meilisearch.notion.site/v1-11-Federated-search-59b30e03383c40729d7541a3dffb0069

TODO

• Ensure the method multiSearch can accept the facetsByIndex option
• Ensure the method multiSearch can accept the mergeFacets option
• Add tests

⚠️ Make PRs pointing to bump-meilisearch-v1.11.0 and NOT main. Please do 1 PR for all of these changes, and not several.