support both pyside2 and pyqt5

[hannesdelbeke]

Currently bqt is tied to pyside2
If we want to use pyqt5, bqt won't work. 😞
this PR adds support for both, using Qt5

but do we want this to live inside this repo, so people can just drag n drop all code into blender and it works?
or do we want to only support pip install, and not include qt5 itself in this repo?

This needs discussion on future direction of bqt, @friedererdmann @bob-white @Amatobahn

[friedererdmann]

Hey! From the looks of it this is the abstraction is very much like Qt.py, correct? If that's the case, should we consider pushing these binding updates to Qt.py and consume from there instead?

[hannesdelbeke]

(this PR also includes sys arg passing to QT modules)
moved that to a separate PR which we can merge in first #26

[hannesdelbeke]

Hey! From the looks of it this is the abstraction is very much like Qt.py, correct? If that's the case, should we consider pushing these binding updates to Qt.py and consume from there instead?

hey, believe this might be related to a newer version of python in blender, or maybe a qt incompatibility .
I used to use qt.py for everything. so think why i didn't here was cause I ran into issues.
would have to test again since it's been a while

qt5 is more recent than qt.py
they serve the same purpose.
qt.py can handle more qt versions, but believe this is because marcus did some hacks for some of the new libs
whereas qt5 is clean without hacks

[hannesdelbeke]

• might be worth swapping to https://github.com/spyder-ide/qtpy for futureproofing. it supports qt6, which fixes some bugs in newer python versions. I've noticed qt5 not working anymore due to bugs in a few cases.
  but would not be possible to embed it, instead it'd be a dependency
• qt.py doesnt support qt6, see Add PySide6 support mottosso/Qt.py#367
• qt5 is an upgrade, assuming you dont need support for pyside1 and qt4, see marcus his post Qt5.py mottosso/Qt.py#294

[hannesdelbeke]

tbh think for now we can just leave it with pyside2, and I could remove this qt conversion from the alt tab PR.
Don't think this change is vital.