Replacement KCM to configure kwin rules, using a QML-based UI.
After some work on the task T12729, it is almost feature-par with the previous module, and adapted to the recent move to KConfigXT. I'm uploading it now as a patch, so it is easier to be reviewed by more eyes.
Currently, the module is installed under a different name (`kcm_kwinrules_qml`).
SCREENSHOTS:
{F8119354}
{F8129507}