Automatic core module docstring description

[bhausleitner]

Prerequisites

• [ x ] Put an X between the brackets on this line if you have done all of the following:
  • Reproduced the problem in a new virtualenv with only neuralprophet installed, directly from github:

    git clone <copied link from github>
    cd neural_prophet
    pip install .

  • Checked the Answered Questions on the Github Disscussion board: https://github.com/ourownstory/neural_prophet/discussions
    If you have the same question but the Answer does not solve your issue, please continue the conversation there.
  • Checked that your issue isn't already filed: https://github.com/ourownstory/neural_prophet/issues
    If you have the same issue but there is a twist to your situation, please add an explanation there.
  • Considered whether your bug might actually be solveable by getting a question answered:
    • Please post a package use question
    • Please post a forecasting best practice question
    • Please post an idea or feedback

Summary

The current version of the Sphinx documentation framework also allows for documentation via the use docstrings. We want the core modules of the neural prophet library to be documented on our documentation page (neuralprophet.com) respectively. Thereby, changes of the core modules should be automatically reflected in the documentation of the core modules.
Currently, Sphinx does only allow for "downward referencing", i.e. references to files that are located in a folder with higher hierachy is not possible:
https://stackoverflow.com/questions/10199233/can-sphinx-link-to-documents-that-are-not-located-in-directories-below-the-root
sphinx-doc/sphinx#701

Example Project

https://pytorch.org/docs/stable/futures.html
http://docs.pyinvoke.org/en/stable/api/__init__.html

What is the current behavior?

Core modules are not documented at neuralprophet.com

What is the expected correct behavior?

Changes of the core modules should be automatically reflected in the documentation of the core modules.

Relevant logs and/or screenshots

Possible fixes

Check how other repositories are dealing with this issue.