First step to move the UI parts that are relevant for creating,
editing (and extending) a reference to it's own class.
There remains some duplication because of the sub-referencing in
Citoid currently depending on the static properties to build its
own editing interface.
More patches follow, I just wanted to keep it small for reviewers.
Bug: T369005
Change-Id: I8588cde1a54cd505a57a36ed97fc591653c9fb6f
