Install and configure BlacklightDates2SVG gem. (not in UI yet)

This commit also removes the Frda::RangeQueryDates class as that has now been moved to the DateRangeSolrQuery gem which is included by BlacklightDates2SVG.

The before_filter and controller solr_search_params_logic is now in the BlacklightDates2SVG gem, so if we remove that, we'll need to re-introduce that logic ourselves.