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

#4: bug fix done for nested stationmeta (inside timeseries record); still left to do: clean up of code and adapting pytests

#11: started adding descriptive text for automatic openapi documentation (especially for use documenting metadata)

#4: nested download for station inside timeseries still not working properly, but at least shows some information; upload after gitlab crash

#4: nested download was extended for timeseries; TBD: showing nested station information is not working yet; also changed programme from many-to-many to 1:n

#3: added unique constraint to controlled vocabularies; added foreign keys (controlled vocabularies) to models

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

#3: toar_controlled_vocabulary is used for downloading timeseries, pytests are added for timeseries; not yet working: how to show human readable fields inside nested models (how is this 'conversion' done automatically?)

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

#4: defined association tables also in models; now using one base for the whole app 'toardb'; this has now also to be adapted to test_base

#4: nested upload/download for roles (timeseries) working in production and pytest (uploading codes not human readable version)

#4: code completely messed up, but nested upload working; nevertheless download is NOT returning the nested view

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