Qt for Python (PySide/Shiboken)

@skinkie I did it using Meson (https://github.com/SciQLop/SciQLopPlots), the best way I found was to use advanced search on GitHub to find as much projects building PySide6 bindings. The funny part was that even with no support in Meson it didn't look much scarier than with CMake. The really painful part for me is the XML. IIRC I took inspiration mainly from Cutter2 and PySide6-QtADS.