Draft: tests: move tests execution from setup.py to tox
Integration of various commands via setuptools is going to be deprecated, so we are moving that to tox. Namely pytest and flake8.
It will also help with testing multiple python versions in sane manner. Use python 3.7 as default interpretr for now.
It also resolves following warning:
WARNING: flake8 setuptools integration is deprecated and scheduled for removal in 4.x. For more information, see https://gitlab.com/pycqa/flake8/issues/544
Please note that:
- python 3.6 is skipped, because pyuci requires python >=3.7
- python 3.8 is skipped, because future versions of TOS uses python 3.9
- we would have to create aditional docker images with different python versions or add multiple python3 to docker image