Support additional metadata

[dac514]

Description

SWORD V1 uses METS as metadata. We test our plugin against the mets XML Schema Definition.

• https://github.com/pressbooks/excalibur/blob/dev/tests/data/mets.xsd
• https://github.com/pressbooks/excalibur/blob/dev/tests/test-swordv1-packager-metsswap.php

In theory, anything that passes our automated test is supported. Here's an example of someone adding http://purl.org/dc/elements/1.1/relation to their implementation (SWORD V2). We could make similar tweaks to our plugin:

• 4Science/swordappv2-php-library@4da1326

That being said, our experience is that DSPACE is sometimes lacking in what it supports. So trial & error and looking at the DSPACE source code to see what actually works is par for the course.