Konfigurator: Avoid needing to apply setWhatsThis() and setToolTip() before calling createSpinBox()
Modify createSpinBox(...) in order to require a QLabel as an argument,
therefore applying setWhatsThis(toolTip) and setToolTip() to
that QLabel is done automatically (and those steps do not have to
be remembered by developers).
Differential Revision: https://phabricator.kde.org/D29546