Port to PyQt6

[nilsholle]

We ported PyRHEED to PyQt6, along with a lot of code reformatting, dependency updates and some bug fixes. We also added building PyRHEED into a portable Zip-file (with all dependencies included) that can be run on any x64 Windows PC.
You can find the code here: https://zivgitlab.uni-muenster.de/ag-salinga/pyrheed
Feel free to use the improvements as you like.

[yux1991]

Thanks for your contribution! Do you mind create a pull request and then we can merge the changes after a code review?