Added features to OAI-PMH API. refs #7469

Added embedding of digital objects in records returned
by OAI-PMH queries. Added API key authentication.

Digital objects are embedded in the <about> tag at an
Atom XML feed.

API keys can be generated for individual users, via the
user admin interface, and optionally required for authentication.

Smaller changes:
* Removed OAI disabled page.
* Got rid of redundant OAI-related setting.
Include qtSwordPluginWorker in new jobs process

- Add ability if qtSwordPlugin is enabled
- Use new job classes

Refs #7641
Fixes in DIP upload process, refs #7641

- Do not save target IO at the end, it was creating nested set problems,
  but update it in the ES index
- Register namespaces and use Xpath queries to allow namespaced and not
  namespaced METS versions
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