Documentation: Add initial docs setup

[activus-d]

This pull request adds documentation setup, including a GitHub Actions workflow to build it.

I've modified the docs/Makefile to use sphinx-autobuild, which watches for changes in the source documentation files:

# Start a local development server to automatically rebuild and serve the HTML documentation 
# whenever changes are made to the source files.
run:
	sphinx-autobuild "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)

Also, I've added instructions for building the documentation locally in django-otp-webauthn/DEVELOPMENT.md.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.0%. Comparing base (5e741ba) to head (9e04b54).
Report is 49 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##            main      #31      +/-   ##
=========================================
+ Coverage   83.4%   100.0%   +16.5%     
=========================================
  Files         13       13              
  Lines        683      683              
  Branches      57       56       -1     
=========================================
+ Hits         570      683     +113     
+ Misses       111        0     -111     
+ Partials       2        0       -2     

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[Stormheg]

Good progress! Thanks for working on this @activus-d and your help in setting this up ❤️

I've left a couple suggestions. One other request that I have is if it is possible to show an 'edit on github' link like shown in the top-right corner here: https://django-tables2.readthedocs.io/en/latest/

I sometimes use such links to quickly go and propose fixes for minor things like typos. Saves me time looking for the right file to edit.

[Stormheg]

@activus-d don't we need to make the documentation available somewhere? Or did you consider that out of scope for this PR?

If it helps, I registered with ReadTheDocs and connected this repository, in case we wanted to host the docs with them.

[activus-d]

Sure, the docs would be deployed, and I can make a pull request or push a new commit to set up deployment to ReadTheDocs once you’re cool with the initial configuration and setup here. Let me know your thoughts!

[Stormheg]

@activus-d for the check errors, you can install and use pre-commit which will perform validity checks on the files you changed when you are creating a git commit out of your changes. See the instructions in DEVELOPMENT.md

[Stormheg]

Looks great to me!