Limit distribution chart query to doc type

The distribution chart issue such queries:

https://intrapre.nuxeo.com/nuxeo/site/es/nuxeo/_search?

however, in case we'd like to use the _all index resolver, we should allow to also pass the type as a path param in order to consume org.nuxeo.elasticsearch.http.readonly.Main.searchWithPost(String, String, UriInfo, String) and therefore better restrict the index we are querying.