Added DataCite XML based metadata mapping option for EZIDIdentifierProvider module.
Merge pull request #621 from umd-lib/ezid-metadata-mapping

DS-2119. EZID IdentifierProvider Metadata Mapping.
In the interest of time, merging this despite a problem with the transform, for which I already have a solution.  A separate PR will provide that solution.
Add a modified transform to meet EZID requirements.

The EZID provider depends on the registrar to generate and return the
identifier, so it cannot supply one in the request. But the DataCite
XML schema requires an "identifier" element. A new transform is
offered, which generates an empty "identifier" element, satisfying
EZID.
Merge pull request #734 from mwoodiupui/DS-2119

[DS-2119] Add a modified transform to meet EZID requirements.
DS-2230 Mirage2 collection strengths not displayed