[WIP]: Port away from deprecated QSignalMapper
Summary:
Most of the cases are pretty straight forward. The exception was KoFormulaTool
WIP since there are still some instance of QSignalMapper
Test Plan: Change in KoFormulaTool were manually tested
Reviewers: #calligra:_3.0, KF6, dfaure
Reviewed By: KF6, dfaure
Subscribers: danders, dfaure, Calligra-Devel-list
Tags: #calligra:_3.0
Differential Revision: https://phabricator.kde.org/D25664