Allow islandora_solr_metadata display for citation, thesis objects

Implements islandora_solr_metadata display for citation, thesis objects.

Checks to see if
* _islandora_solr_metadata_ is installed
* A field configuration has been created for the current content model
 and if both are true, renders the display with the user-configured solr metadata fields. Otherwise, it falls back to the old COINS method defined by this module.

There is some copy/paste code here between thesis/citation that could be refactored/expressed into more efficient methods, but I felt it best to keep hooks and templates completely separate for unique content models.
Diddo url() function above lines 30-31.