Add black and flake8 as linter check

[delijati]

I use for all my projects https://github.com/psf/black and https://github.com/PyCQA/flake8. With this config .flake8.
This would prevent all this formatting changes ;)

Example for my pipeline https://gitlab.com/delijati/tchotcho/-/blob/master/.gitlab-ci.yml#L11

[flake8]
# https://github.com/psf/black#slices for E203
ignore = E501 W503 W504 E203
max-line-length = 88
max-complexity = 10

[KiraPC]

Introduced!