Introduce pre-commit hook and formatter

[djs0109]

In order to simplify the review process, we should introduce the pre-commit hook with a formatter.

requirements:

• pep 8 conform
• identical code length control
• what else?

todos:

• [ ] test the formatter locally
• [ ] run formatter once for the current master branch, and check the results
• [x] create pre-commit hook
• [x] update setup.py
• [ ] update readme

[github-actions[bot]]

Branch 341-Introduce-pre-commit-hook-and-formatter created!