Currently the two available input types are:
- GMessageBox::InputType::OK (default)
- GMessageBox::InputType::OKCancel
Based on your choice, GMessageBox::exec() will return ExecOK or ExecCancel.
Currently this will be used by the WindowServer to show some dialogs.
This is needed since WindowServer can't use LibGUI and reimplementing
message box functionality inside WindowServer would be silly. :^)
The only dialog supported in this initial version is --shutdown