Investigating moving some tutorials to Tools, and adding more tools

[plaindocs]

Not yet ready for public consumption

Looking at how a structure might look with only one RTD tutorial, moving Sphinx and Mkdocs stuff to a Docs tools section, leaving space to add more.

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:books: Documentation previews :books:

• User's documentation (docs): https://docs--11317.org.readthedocs.build/en/11317/

• Developer's documentation (dev): https://dev--11317.org.readthedocs.build/en/11317/