Allow to use Solr Grouping in the Solr API

Solr Grouping allow to retrieve information by grouping document who share the same field information. It can be useful to perform requests when a "groupBy"-like operator is needed.
See documentation about Grouping in Solr: https://solr.apache.org/guide/8_8/result-grouping.html. Note that the doc specifies to better use collapse/expand, but collapse actually doesn't provide information about the number of document grouped, which is generally the information we want.