Remove sphinx from requirements

[TTitscher]

The current requirements contain

sphinx
sphinx_rtd_theme

which are not needed to install the package, e.g. in another project or a CI pipeline.

To build the documentation locally, we could have a requirements_website.txt or so that needs to be installed once by a user. But @joergfunger, how does the readthedocs integration work? I did not find the place that tells readthedocs what to build. I assume, by default, they look for a conf.py and index.rst and run sphinx themselves. Is that correct? In that case, the requirements_website.txt plan would work.

[joergfunger]

For your first question, I think this is what Readthedocs does. However, you could still create the documentation (e.g. to test before the submission yourself). I think they way to go could be to follow the approach here that actually splits the requirements into the ones required for using the package and for developing it. There, it might make sense to keep the sphinx related stuff for the development and remove it from the user section. Btw, I tried to incorporate that in a branch (that was originally intended to make a conda package, this part is not working, yet, but there is already a merge request), so I would suggest adding this there.

[TTitscher]

I could not find much information on that in your first link from python.org. Anyways, on your branch you added the actual dependencies numpy,scipy in setup.cfg and the additional packages are in environment.yml, right?

As an easy fix, I suggest to only have numpy, scipy in our current setup.py and document somewhere that you need sphinx, ... for running doit website.