Update to Qt6 and MO2 2.5.0

[SilentSpud]

This fully updates the code to PyQt6. MO2 2.5.0 still throws errors that PyQt5 isn't present even with the try-except statements, so I removed it completely. Unfortunately, this comes with some caveats:

• Qt6 doesn't have pyrcc, so it has to use Qt's rcc, which requires installing Qt 6
• Qt's rcc generates a PySide6 import, so resources.py has to be edited to use PyQt6
  • I switched to a powershell build script to change the import automatically
• PyQt6 isn't on GitHub, only PyPI, so the alternate build instructions don't work anymore

This also includes a fix for hide type being case sensitive

[SilentSpud]

Alternately, we can just install PyQt5 alongside PyQt6 and keep using pyrcc5, but that'd still require editing resources.py