Expanding on the addition of docstrings in code, this adds python module API docs to sphinx documentation.
A developer can preview what this might look like by running this locally:
```
tox -m docs
```
The option `-W` is added to the tox env so that warning messages are considered errors.
Adds doc generation using the above method to the test GitHub workflow to catch documentation problems on PRs.
Some docstrings have been reformatted and fixed to satisfy errors generated with the above setup.
* Further nested lists rendering fixes
* Remove a couple of sphinx warnings
* Fix bootstrap.users.password description
* Boto->boto3 in README's
* Split configuration docs and move some lines across files
* Fix a typo
Sphinx' add_stylesheet() has been deprecated for a long time and got removed in recent versions of sphinx. If available, use add_css_file() instead.
Close#2079.
Alexander Kukushkin