Add support for a DSpace internal quality assurance source

[abollini]

Please note that this development has been funded by the University of California - California Digital Library.

This PR adds the endpoints required to implement a "DSpace Users" driven quality assurance source named "DSpace User Corrections". This gives the possibility to create quality assurance event, retrieve quality assurance event created by the current user and delete them.

The DSpace User Corrections manage different types of correction providing future proof extensibility that can be discovered via the proposed new REST API correctiontypes endpoint.

The REST and Angular PRs are following that will use this new endpoint to provide the ability for authorized users to request withdrawal or reinstate of an item managing the request within DSpace instead than rely on email or other external communication.

Please note that

• this is an additional source for the Quality Assurance framework that has been introduced here Rest contracts for qaevents, qatopics and qasources endpoints #181
• there is a partial overlapping with the COAR Notify PRs , as this contribution is significantly smaller in terms of changes it could be appropriate to attempt to review and merge before the COAR Notify PRs so that the review of the latest will become easier Coar Notify Integration #249

[tdonohue]

@abollini : Overall this looks good. But, I've noticed that we seem to be missing documentation for at least a few new endpoints created by this feature. See inline below

[tdonohue]

👍 Thanks @abollini for the responses. On second look, this all looks good to me.