A lot of docstrings, and revision of behaviour when moving the dataset folder around

First, the intention was to check the behaviour when checking a folder dataset around. This seems to work correctly, as the root_path is updated.

Then, I additionally took care of updating and adding all docstrings, and harmonizing the default in this. I believe this is now done consistently throughout the full toolbox, but a double check should be done.

Finally, some deprecated functions were removed.