finished UBA NRT with the new database structure using the REST API (also added minor fixes to REST API and NRT changelog behaviour)

#3,#4: nested uploads/downloads using controlled vocabulary; still to investigate: how to load enum_tables at beginning (this commit is a workaround)

almost done: using human readable controlled vocabulary for upload; TBD: using human readable controlled vocabulary for download, adapting pytests

created ONE toardb app, also adapted pytests for toardb app (still very last test will throw an error for teardown; inserted example for url percent encoding