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

#3: now nested human readable download is established for timeseries; TBD: do this for all other modesl

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

#7: default values for stationmeta_global were defined; #4: nested upload tested for 'stationmeta_global' (not defining all metadata -- getting the rest from default values)

#4: nested upload for stations done; TBD: more testing (esp. pytest), use controlled vocabulary (related to #3)

#4: nested download for stationmeta realized; TBD: uploading of new test database, nested download for stationmeta

#8: common base and test base is in place (but teardown of test_base has to be worked on for chained 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

adapted sphinx documentation to new structure (ONE app); some pretty printing (fastAPI does not provide sphinx extensions like django)

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