DATASOLR-121 - Add ability to add more group params
introduced GroupQuery in order to perform group queries to solr,
resulting in a page of GroupResult (parsed from solrj GroupCommand).
Revert "DATASOLR-121 - Add ability to add more group params introduced GroupQuery in order to perform group queries to solr, resulting in a page of GroupResult (parsed from solrj GroupCommand). "

This reverts commit f19a7403dbd0ec497f37ca26655c793f73041c89.