Unify and enforce formatting

[matthiasr]

This came up in #414 and I ran into it a few times.

Unified and automatically formatable styling makes it easier for different contributors to work on the code. Instead of piece-meal changes that make individual PRs difficult to follow, I would like to do one big bang reformat, ideally while there are no other open PRs.

What are the most common formatters? Ideally we should not require any special setup from users with auto-formatting IDEs. At the least, users of (say) IntelliJ, Eclipse, and VS Code don't need to do anything to stop their editor from enforcing the wrong format; better would be if these also automatically enforce the right format.

In any case, we should enforce this formatting in PR pipelines, probably in a separate job for clarity.

[matthiasr]

cc @or-shachar because I am sure you have opinions on this 😄

[or-shachar]

I made a little research and came up with #418
I do want #414 to be merged first so I won't have serious conflicts :)