Add linting and static checks

[johscheuer]

I'll enable pylint in another PR as this would require some more changes to the Python code. All code changes are coming from black.

[ploxiln]

For what it's worth, my 2c, I prefer just using "flake8" (which is just "pyflakes" + "pycodestyle" + config/ignore support), because black and pylint cause so much churn on so much unnecessary stuff.

But anyway, I recommend changing the max-line-length to 100 or 120 chars, from default 80. That will reduce some of this churn due to "annoying folding".