Fix "Add author" behaviour and other UI fixes

[mietcls]

Fixes "Add Authors / Creators":

Datasets

• For datasets it no longer says "Add author" but "Add creator" in line with the roles

Publications (temporary fix, needs to be extended)

• For publications it no longer says "Add author" for issue editors and book editors. This is not ideal, as we should nudge to add editors, but the call to action would never go away as those publication types do not have authors at all.
  • what it looks like for editor publication types:
  • what it looks like for others:

Other fixes

• Aligns badges
• Circumvents annoying double lines (See #1623)
• Aligns "Add department" to "Add projects" behaviour
• Removes superfluous code for departments