Remove as deprecated marked classes and functions
Summary:
The in Qt 5.13 as deprecated respectively obsolete marked classes,
methods and functions were substituted by its, in the compiler
message or documentation suggested, alternatives.
Test Plan: Compiler runs without warnings
Reviewers: KDE Edu, apol
Reviewed By: apol
Subscribers: apol, kde-edu
Tags: KDE Edu
Differential Revision: https://phabricator.kde.org/D22497