docs build borked

[lkubb]

Generally, there are two hard dependencies missing from docs.in: furo and sphinx-copybutton.

Then, there are two separate, conflicting docs build jobs:

docs, which is intended to work the same way the Salt docs do, but fails because:

1. .pre-commit-hooks/make-autodocs.py by accident strips the module names from the doc file names
2. autosummary is instructed in docs/conf.py to generate its own stubs via autosummary_generate = True, which conflict with the other ones
3. docs/all.rst is written with the second method in mind

This is the one that will be executed by the workflows currently.
Another issue is that the hook script does not account for no_saltext_namespace (thus rendering module names as src.mypackage.modules.foo_mod) and exits with 0, even if it created/changed files (pre-commit thus does not fail).

Then, docs-html seems to have been introduced because the first did not work. I think it is intended to be used like nox -e 'docs-html(include_api_docs=True,clean=True)', for example. This fails because all.rst references a file that is never being generated: states.rst (it was probably meant as saltext.foo.states.rst, modules.rst exists because it represents all the modules in the package). Removing this reference results in a - imho - needlessly complicated and very nested output. I might be missing something though.

Additionally, the all.rst index is not parametrized with the loader modules that were selected.