API: Make KReportDesignerSection constructed by KReportDesigner, hide the zoom handler, use more stack, some renames
Summary:
Improve APIs, hide some internals deeper
Also review Kexi https://phabricator.kde.org/D5121
Test Plan: Build, run tests and the example app
Reviewers: piggz
Reviewed By: piggz
Tags: KReport
Differential Revision: https://phabricator.kde.org/D5120