Developer Environment Improvements

[egeakman]

Here are some suggestions to improve the developer experience:

Dependency management

• Replace pipenv with something else Streamline dependency management #138

Developer Tools

• Use pre-commit and pre-commit.ci
• Use black, isort and ruff with pre-commit
• Remove flake8 in favor of ruff

[NMertsch]

Let's remove black and isort as well, ruff can do both tasks.

But let's first get the functional stuff done for the conference before we do a major rework of the project structure. We could also do that during the sprints or after the conference.