Use black for automatic code formatting

[nirs]

Using black we can get good automatic formatting that can be done automatically in most editors and easy to check in the CI.

This can help new contributors to write more idiomatic code and avoids spending time on formatting issues in reviews.

Examples from ramen project on how to integrate black:

• integration with vim: https://github.com/RamenDR/ramen/blob/main/.vimrc.example
• flake8 configuration: https://github.com/RamenDR/ramen/blob/main/.flake8
• Makefile with black check: https://github.com/RamenDR/ramen/blob/main/test/Makefile
• CI workflow with black check: https://github.com/RamenDR/ramen/blob/8d2ed78f9b78e8c6ddfd7980a09ed01a1cb6f466/.github/workflows/ci.yaml#L99