Similar to QWidget::parentWidget(), but not tied to QWidgets.
Allows to start removing some asQWidget() calls, as seen in Frame::floatingWindow(),
did it for POC.
Still need to find a generic way to compare 2 QWidget pointers
In many cases we need to access widgets that weren't created by
KDDW, in that case we have no View. Since all our APIs want to
deal in View and not in QWidget, we need a way to wrap stuff like
QWidget::window() and windowHandle()
All methods are unimplemented. Will only implement those that
are required/used.
Controllers don't have any GUI and don't depend on the frontend
technology.
Views are implemented in a specific GUI tech (QtWidgets, QtQuick, etc).
For now only QtWidgets work. There's still a lot to decouple.
This will make it easier to introduce non-Qt backends.
