Add checker for python code

[nashif]

Check for python syntax using one of the many linters:

• flake8
• pylint
• ..

preferably this should work on diffs rather on complete files.

[marc-hb]

BTW here's pylint's most missing feature, especially in the context of focusing on new code and ignoring warnings on existing code:

usefulpylint() { pylint "$@" | sort -t ":" -k 2,2n ; }
usefulpylint -E scripts/sanitycheck

[ulfalizer]

Only takes ~5 seconds or so run pylint3 on all .py files in the tree, so for stuff that should always generate a failure, it's easy to do that instead.

[marc-hb]

Duplicate of issue zephyrproject-rtos/zephyr#10338 ?