Generate a separate field for each value of /mods/identifier/displayLabel in an exhibit data-contingent indexing #555
Description
Story:
The displayLabel value for identifiers can provide important context and distinguish between different systems of identification used for the same object. Exhibit curators would like to display identifiers in separate fields by displayLabel to provide this context for users.
Acceptance criteria:
A separate display field should be available for each value of /mods/identifier/@displayLabel appearing in the exhibit metadata, labeled with that value and containing the value of the corresponding /mods/identifier.
Fixture objects are in #889, and 1-5 apply