Update Bauh to Qt 6.6.2
Updating from Qt5 to Qt6 mostly took attribute call changes, going from exec_() to exec() and finding a solution for the removed QDesktopWidgets class with QScreen.
I haven't tested all the functionalities, like flatpak building for example or checking all the setting options hand-by-hand. Installing/uninstalling apps, searching for packages, changing some searchbox options, going through settings tabs, getting recommended packages and others are working on my machine, but most likely we would need to atleast check the Flatpak building as well atleast if my updated code seems to be alright.
Related issue: #359
@PrivateN00b thanks for your effort in converting the current code base to QT6. I'll retest everything to make sure we don't have regressions, so it may take some time...
Brilliant job here, looking forward for the Qt6 version !