Major Description
Until the time we'll be able to work on the index time aggregation for Solr, we should make it possible to aggregate search results of /foo/bar/jcr:content nodes as their parents /foo/bar as that's what nowadays often done in Lucene index configuration and therefore useful for feature parity.
We can disabled this as soon as we switch oak-solr to depend on oak-search and therefore Solr index gains the index time aggregation feature consequently.