Vito

* Convert boolean masks to uint8 images within `imshow` to ensure OpenCV compatibility.
* Internal adaptations to fix deprecated (NumPy) and changed (PIL) library usage.
* CI updates to [PyPI's trusted publishing](https://docs.pypi.org/trusted-publishers/).
* Code clean up (added type hints, docstrings, ...).

* Deprecated functionality is removed (workarounds for Python versions older than 3.6).
* Most frequently used methods now have type hints.
* Parameter order check to imsave (that's the one thing I alwys mess up when coding without IDE).
* `imsave` now creates the output directory structure if it did not exist.

* Silences the log messages upon import
* `imshow` falls back to PIL if opencv is compiled without GUI dependencies
* Include recent python version in python packaging tests