feature: CLI dispatcher

[flying-sheep]

I made all CLI packages follow a convention:

• def make_parser(parser=None, prog=None) either creates a parser or adds arguments to one that’s being passed
• def run(args=None) either runs from passed args (argparse.Namespace) or parses sys.argv using make_parser

Together, that allows to maintain backwards compatibility, as python -m hatch_jupyter_builder.migrate is still possible and works the same as the new hatch-jupyter-builder migrate.

Fixes #62

Results:

$ hatch-jupyter-builder -h
usage: hatch-jupyter-builder [-h] {migrate,compare-migrated} ...
...
$ python -m hatch_jupyter_builder -h
usage: /usr/bin/python -m hatch_jupyter_builder [-h] {migrate,compare-migrated} ...

positional arguments:
  {migrate,compare-migrated}

options:
  -h, --help            show this help message and exit

$ hatch-jupyter-builder migrate -h
usage: hatch-jupyter-builder migrate [-h] target_dir
...
$ python -m hatch_jupyter_builder migrate -h
usage: /usr/bin/python -m hatch_jupyter_builder migrate [-h] target_dir
...
$ python -m hatch_jupyter_builder.migrate -h
usage: /usr/bin/python -m hatch_jupyter_builder.migrate [-h] target_dir

positional arguments:
  target_dir  Target Directory

options:
  -h, --help  show this help message and exit

$ hatch-jupyter-builder compare_migrated -h
usage: hatch-jupyter-builder compare_migrated [-h] source_dir target_dir dist_name
...
$ python -m hatch_jupyter_builder compare_migrated -h
usage: /usr/bin/python -m hatch_jupyter_builder compare_migrated [-h] source_dir target_dir dist_name
...
$ python -m hatch_jupyter_builder.compare_migrated -h
usage: /usr/bin/python -m hatch_jupyter_builder.compare_migrated [-h] source_dir target_dir dist_name

positional arguments:
  source_dir  Source Directory
  target_dir  Target Directory
  dist_name   Dist name

options:
  -h, --help  show this help message and exit

[welcome]

Thanks for submitting your first pull request! You are awesome! 🤗

If you haven't done so already, check out Jupyter's Code of Conduct. Also, please make sure you followed the pull request template, as this will help us review your contribution more quickly.

You can meet the other Jovyans by joining our Discourse forum. There is also a intro thread there where you can stop by and say Hi! 👋

Welcome to the Jupyter community! 🎉

[blink1073]

Very nice, thank you!

[blink1073]

Failure is unrelated. Thanks again!

[welcome]

Congrats on your first merged pull request in this project! 🎉

Thank you for contributing, we are very proud of you! ❤️

[blink1073]

https://github.com/jupyterlab/hatch-jupyter-builder/releases/tag/v0.6.0

[flying-sheep]

neat, thank you for the quick review and fixing this up with readme changes and so on!