Add isort/black to pyRTE

[tcmetzger]

We are already formatting the pyRTE code with black and isort locally before committing, but we should formalize this as pre-commit hook and Github action.

[tcmetzger]

@sehnem Feel free to pull in @giancastro for help on this one!

[RobertPincus]

Seems like this is completed?

[sehnem]

Yes, it is @RobertPincus and @tcmetzger, the only thing that is not final is that I added some exclusion to the docstrings checks for flake8, but I should remove it when the clouds are ready.