Reduce calls to Solr for CiteProc citations

[maxkadel]

What maintenance needs to be done?

Make it so that displaying citations for SCSB items using CiteProc does not require a second call to Solr. (see #4012 for original implementation).

Level of urgency

• High
• Moderate
• Low

Why is this maintenance needed?

• Having a second call to Solr slows down the user experience, puts more load on Solr, and should not be necessary (there should be a way to make all fields available for display on the initial call to Solr).

Acceptance criteria

• After the show page is loaded, there should not be an additional call to Solr to get the fields needed to display the citation

Implementation notes, if any

See citation_fields_from_solr method in the Blacklight::Document::CiteProc class. (not yet merged as of this ticket writing).