Draft: (not-for-merge) Activity settings: port away from QML
Kirigami >= 5.86 breaks activity settings dialog, making it impossible to override existing activity shortcut, user has to remove it manually first: key presses are silently ignored by window like user has never pressed the key, holding modifier with no reason. Modifier combo should exactly match.
e.g. if there's an activity with Alt+F, Alt+F would be ignored, Ctrl+Alt+F will be processed.
This commit ports away from QML-defined tab to UI-defined tab because something is wrong in QQuickWindow implementation, see details at bug 445277.
Edited by Oleg Solovyov