Docs website change: Pydata docs theme

[zain-sohail]

This PR changes the current readthedocs theme we are using for docs to the pydata docs theme, which supports a lot more features.
Here, we also change the documentation github actions workflow as after building, it will push that versions (like 0.2 etc.) to the docs repo in the sed folder.

The latest main version can be found here: https://opencompes.github.io/docs/sed/latest/

There are some changes to the structure of the documentation (such as seperating user guide, advanced workflows and api) that I saw made more sense but these can be discussed here.

Current main branch is supporting python 3.8 but the pydata theme only supports >3.9 so the workaround is to pip install on the CI for now but in v1, we can change this.

[rettigl]

I generally like the idea behind the new workflow, but suggest some improvements to the structure and layout. See detailed comments.

[coveralls]

Pull Request Test Coverage Report for Build 11766316957

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 91.948%

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Totals
Change from base Build 11662147388:	0.0%
Covered Lines:	6486
Relevant Lines:	7054

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💛 - Coveralls

[rettigl]

@zain-sohail I believe this is also ready now. Please have a final look.

[rettigl]

Fnished from my side

[zain-sohail]

I have taken a look at the develop docs and looks good. Any doc changes, we can always do later. I'd say we merge and see if the switching is working properly. Otherwise we might need to delete the static files and rebuild them.