Native windtail support

[seyeong]

I created a python package called tailwind in the test-pypi environment. The package includes the standalone CLI, and exposes subcommands as a python module. This is an attempt to replace NPM with tailwind in django-tailwind.

Notable things:

• Renamed tailwind to django_tailwind to avoid name clashes. I believe this is the right move as it is specific to Django.
• ~~... tailwind start command is not properly implemented as tailwind.watch is not implemented.~~
• ~~--postcss option is disabled as it is currently failing with tailwindcss CLI as well. See https://github.com/tailwindlabs/tailwindcss/issues/8766.~~
• postcss.config.js has been replaced with the default file from tailwindcss init command.
• plugins in postcss.config.js has been emptied.
• Removed unnecessary sub commands.

Fixes #125 and #140.

Replaces #141