Add dependency on xmlui - dspace.cfg names HIVESubjectAuthority

When updating metadata on an authority controlled term, the authority control plugins named in dspace.cfg are loaded dynamically. One of these is currently HIVESubjectAuthority, which lives in the xmlui module.
Add @Produces annotations to methods that now return JSON
Bug fixes for metadata sync

Disable context authorization when sync metadata
Format titles as “Data from: “
Prevent clobbering fields if manuscript has null values
Tweak messages
When clearing metadata, use Item.ANY if no lang
Cleanup stray comment
Remove unionKeywords - addMetadata already uniques

Intent was to prevent duplicates for keywords that already exist in the
data package, but DSpace Items already uniquify the metadata values, so
unioning is unnecesary - in fact it was altering the order since a Set
was used to prevent duplicates
Fix typo in rejecting submission based on DOI

TRUE != FALSE, knucklehead.