Utils: Rework CheckableMessageBox

Remove function overloads, thes are hard to read, to use and to extend.
I'd even argue this should be a plain default ctor and a few setters +
exec(), pretty much like Process::start() nowadays.

Move "decider" magic into a structure that can be filled ad-hoc outside
checkablemessagebox.cpp paving the ground for:

...removing  aspect dependency from CheckableMessageBox, Instead, add a
convenience function to BoolAspect.  Arguably, the latter is not needed
and could be done on the user side.

Use pointers instead of mutable references for in-out parameter.
Makes the "specialness" visible on the user side.

Pass ICore::settings() centrally as done elsewhere to reduce line noise
on the user side.

Change-Id: Ibb366353d1ea35401723fd05ce05672617a0a8fd
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp

@@ -594,7 +594,7 @@ void CMakeBuildSettingsWidget::reconfigureWithInitialParameters()
         Core::ICore::dialogParent(),
         Tr::tr("Re-configure with Initial Parameters"),
         Tr::tr("Clear CMake configuration and configure with initial parameters?"),
-        settings->askBeforeReConfigureInitialParams,
+        settings->askBeforeReConfigureInitialParams.checkableDecider(),
         QMessageBox::Yes | QMessageBox::No,
         QMessageBox::Yes);