Feature/autoblack

[Elvirarp92]

Format entire codebase to black and add a job to autoformat code to Black on push. Closes #91 .

I have tested it in my own fork and it works fine. Do we want to keep format fixups in their own separate commit? (this is the current behaviour in the job) Or rather amend the last commit in the push to include the format changes "silently"?

I have taken the liberty to remove the duplicate Coveralls badge in README.md - the remaining one references the main branch. I can discard that change if needed, of course.

[zerasul]

nice job