Restructure table of contents, section indices, and landing page

[willingc]

This PR applies Diataxis structure consistently to the guide's contents. It simplifies the landing page and the main contents sidebar.

CURRENT	PR

This PR adds section pages for Overview and References:

Finally the content in the landing page has been simplified and aligned to a Diataxis structure.

---

📚 Documentation preview 📚: https://python-packaging-user-guide--1409.org.readthedocs.build/en/1409/

[jeanas]

I like the simplification of the sidebar.

Would it not be better to move reST files around instead of using ../, even if we need to add redirects? I was a bit confused; I did not think it was even possible in Sphinx to refer to documents outside of a directory from a .. toctree:: directive in a file inside that directory.

[jeanas]

Also, I'm not sure "Reference" is the best place for the "News" page. Perhaps make an "About" folder for "News" and "Contributing"?

[willingc]

Also, I'm not sure "Reference" is the best place for the "News" page. Perhaps make an "About" folder for "News" and "Contributing"?

Since "News" is a historical page that we likely won't continue, I tossed it under Reference.

[jeanas]

In that case, maybe we should just orphan the page?

[willingc]

ping @pradyunsg

[jeanas]

Let's try to move this forward? I'm approving the PR, we can move documents and add redirects later, when we've solved #1408.

[webknjaz]

Should this be changed? We could update just the ToC entry text instead.

[chrysle]

I agree with @webknjaz on that.

Suggested change

	************
	Contributing
	************
	************************
	Contribute to this guide
	************************

[chrysle]

Suggested change

	contribute
	Contributing <contribute>