Adds button to metadata section that will request a new DOI from DataCite. It first queries datacite for the most recently generated DOI, increments the number, and then submits the DOI request. At this point the DOI will be registered in draft mode without metadata. When the publish decision is set, a request is made to datacite to update the status to published (findable) and it updates the metadata (title, year, abstract, authors, type, publisher and url.
I can provide credentials for their test API.
Closes #269 (closed)