Port away from deprecated KDELibs4Support

Summary: kmenuedit seems to work, adding new submenus and items

Reviewers: mlaurent, vkrause

Reviewed By: mlaurent, vkrause

Subscribers: vkrause, plasma-devel, kde-frameworks-devel

Tags: #plasma

Maniphest Tasks: T11566

Differential Revision: https://phabricator.kde.org/D24603