Documentation of tables and functions + Best Practice

[KonstantinWilleke]

The user does, as of now, not have a good idea what the expectations of nnfabrik are. The specifications are not listed explicitly. So the functions, specifically in builder.py, have to extensively documented. As well as the tables in main.py.
The logic of inputs and returns of models/datasets/trainers should be documented extensively.

Supply the user with best practices. This should be part of the documentation.
Part of the best practice:

• All models should accept inputs and data_key, as well as **kwargs. So that every model works with every dataset. but the model has to warn the user if kwargs are ignored (otherwise its prone to error).

[ArneNx]

Improve main.py docstrings

[ArneNx]

What is the status of this @KonstantinWilleke, @mohammadbashiri ?
Are we at a point where we're satisfied with our documentation?