feat(search): configurable facets size

[abulte]

Related datagouv/data.gouv.fr#1432
Related datagouv/cdata#1054

This lets the consumer use a query parameter ?facet_size__{facet_name}={value} to request more bucket values for a facet from ElasticSearch.

There's a configurable MAX_FACET_SIZE that defaults to 500. Increasing the facet size leads to more resource usage in ES, this a defensive value that needs to be discussed.

Not all facets can be configured, it's in a configurable_size_facets[] list on the adapter. Only organization_id_with_name is in there for now. Listing the facts was needed to generate a proper query arg parser, and I took the opportunity to limit the facets that can be configured. We could include more facets by default. We could also refactor to auto-list all the supported facets, but it's a bigger rework ⬇️.

⬆️ This rework is proposed in ecolabdata#10, I can merge that one into this one if it makes sense.

For ecologie.data.gouv.fr, this would let use facet_size__organization_id_with_name=200 for the filter from datagouv/cdata#1054 to have all the values from our universe. It would also need to be wired up in cdata's GlobalSearch.

Reference: https://www.elastic.co/docs/reference/aggregations/search-aggregations-bucket-terms-aggregation#search-aggregations-bucket-terms-aggregation-size

[abulte]

@ThibaudDauce can't assign you as reviewer from a fork... Can you have a look? 🙏

[abulte]

Idea: use SOLR DSL for url queries https://solr.apache.org/guide/solr/latest/query-guide/faceting.html (thanks @streino)