Update UI for controlled vocabulary browsing to search by identifier

[dannymandel]

In isamplesorg/isamples_inabox#362 we are moving off the vocabulary labels, and moving everything onto the vocabulary identifiers. As part of this, the UI needs to be changed to query solr by the identifier value rather than the label value.

I updated some test records, and was able to verify that the hierarchical UI did not function correctly without changes.