DOI test mode now only changes the prefix.

Removed special handling of test mode DOI lookup and removal to fix the discrepancies when registering a Package DOI.
Remove manuscriptNumber from alternateIdentifiers
Enable Test mode for now
Register DOIs when entering publication blackout
Refactored DOI registration for publication blackout

If item is in blackout, use datadryad.org/publicationBlackout as the
target
Move logic to check blackout to helper class