Case by case fixtures modify

Moves fixtures to specific directories.

JSON docs under `spec/fixtures/solr_documents` will be indexed for use in feature testing/development

JSON docs under `spec/fixtures/test_cases` could be used instead of creating json records in specific unit tests.  For example see: https://github.com/geoblacklight/geoblacklight/blob/master/spec/lib/geoblacklight/references_spec.rb#L6

Instead of creating a a record for each of these tests, json files could be used or this could be included in a Ruby class. Creating ticket #227 for evaluating whether or not to do this