Automatic formatting using black

[aecio]

This PR configures a Github action to check if the code is properly formatted using Black. The CI will fail if the code is not properly formatted.

Make sure you have black installed:

pip install black

To format the code, anyone can use the command before committing your changes:

make format

Or you can use Black directly:

black ./bdikit/

You may also use Black through a VSCode extension to format files individually as you code: https://marketplace.visualstudio.com/items?itemName=ms-python.black-formatter