Let the user confirm closing Qt Creator

I'd like Creator to ask me for a confirmation before closing itself, especially when I pressed Alt+F4. This should be an opt-in feature which I could enable in the preferences.

The rationale for this is that the shortcuts I'm using a lot (F4, F5, Alt+3, Alt+5) coincidentally are very close to Alt+F4, so sometimes I accidentally exit Creator. In that case it would be helpful if Creator was a little less obedient.