Transform JSON DC metadata into CSV

This allows Dublin Core metadata to be represented in JSON format
along with the current CSV format. A new microservice is added which
translates the JSON metadata into CSV during the transfer phase.

Refs #6266.
archivematicaCreateMetadataCSV: pep8 cleanup
archivematicaCreateMETS2: some pep8 cleanups
archivematicaCreateMETS2: Represent DC term refinements

This allows refined DC terms to be represented, such as
"dc.description.abstract". This is implemented following the advice of
the Dublin Core XML guidelines:
http://dublincore.org/documents/dc-xml-guidelines/#note1

Refs #6266.