Autodocs and more!

[waynew]

This is a pretty major change, but hopefully all welcome!

Here's a list of what I've done:

• Improved this README - now coming to the project on GitHub it should be clear
  how to use it.
• Simplify requirements - put them in the setup.cfg, also made it so there are
  project requirements as well as extras for tests/dev/docs building
• Make README cooler - now when the project is created it will have a README
  with some sample quickstart
• Tweaked the commands to run after project creation
• Defaulted to Salt 3003+ as a dep
• Added some info for installing enchant to be able to build the docs
• Updated noxfile to only do a single install, rather than installing deps with
  one go and then source/project with another
• Added autodocs hook - Now it's impossible to forget to add a docs file for
  newly added files. It's not a super robust script, but it should work well
  for most extensions.

Let me know if there's anything I missed -- here's how I tested it:

cd path/to/salt-extension
docker run --rm -it -v "$PWD:/saltext/" -p 8000:8000 python:3 /bin/bash
# in container...
git config --global user.name "John Doe"
git config --global user.email "[email protected]"
cd && rm -rf fun && mkdir fun && cd fun && python3 -m pip install /saltext/ && create-salt-extension -A "John Doe" -E [email protected] -U https://example.com -l states -l module -S "hello bello" -L apache fun

Then just followed the output text. Used python -m nox -e docs to build the
docs and then served up with cd docs/_build/html; python -m http.server.
Should be accessible in your browser at https://localhost:8000 at that point.

[s0undt3ch]

Solid!