Docs: Relabel howto guides for Git repository configuration (Diátaxis)

[benjaoming]

This tweaks the accuracy of two howto guides that can be hard to distinguish. Not least because of the existence of a third guide "How to connect your Read the Docs account to your Git provider".

• Relabel guides
• Move files
• Fix up references that were initially wrong (but more evident now that filenames are fixed)
• Added some new content for "How to automatically configure a Git repository" which had gone a bit stray
• Create redirects for 2 moved pages

Reviewing

I tried to keep this simple and only add clarity where the howto can perhaps create confusion about how Read the Docs works and which howto to use.

• Are these good tweaks?
• I added new text to "How to automatically configure a Git repository". I think it fits as a howto guide since it aligns with information that I imagine users would look for.. even though there is nothing actionable, the guide now takes a practical approach.
• While doing the above, I uncovered some content for a feature reference :)
• Other small things to fix here while we're at it?

Refs: #9747

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📚 Documentation previews 📚

• User's documentation (docs): https://docs--10247.org.readthedocs.build/en/10247/

• Developer's documentation (dev): https://dev--10247.org.readthedocs.build/en/10247/

[ericholscher]

This does a good job of clarifying the guide names. Should be mergable with a couple fixes.