Facets and filters behavior

[curquiza]

Implement behavior in this spec: https://github.com/meilisearch/specifications/blob/main/text/0027-filter-and-facet-behavior.md

• The facetFilters parameter during the search is removed. Only filter can be used.
• The users need to set the attributes to attributesForFaceting to use the filters during the search via the filter parameter. But they don't have to specify the type. Milli must accept only attributesForFaceting in an array like this:

{
  "attributesForFaceting": ["author", "price"]
}

=> this is the current MeiliSearch v0.20.0 behavior: https://docs.meilisearch.com/reference/api/attributes_for_faceting.html#attributes-for-faceting
=> this means milli has to create two data structures: one for the strings and one for the numbers. No conversions are done in the user documents: "price": "12" is not considered as a numeric field and should be in the string data structure.

• when applying filter with a numeric operator, milli should search into the number data structure only. Otherwise in both data structures. More detail in the spec.
• The filter parameter can accept both syntaxes: string (with OR/AND/NOT) and array. An element of an array syntax can accept the string syntax. The first depth of the array syntax is combined with ANDs, the second depth is combined with ORs.

Feel free to complete my issue @Kerollmops with all the technical parts we need to implement these and if some parts need to be implemented on the transplant side 🙂

[curquiza]

⚠️ I updated the issue, the parameter filters is now filter.