Project solr should use native apachesolr query strings instead of custom ones

While working on drupalorg, I've had to create quite a few epic form alters to transform the custom query strings put out by project_solr_browse_projects_form() into ones that apachesolr understands. Example (term_vid_3 needs to be passed as f => im_taxonomy_vocabulary_3:tid). This patch moves this back into project solr instead.

#1838692: Keeping up with project solr