Por all usages of QWindop/windowHandle to KDDockWidgets::Window

Removes a lot of asQWidget() code and is also prepared for non-Qt
views.

src/qtquick/views/ViewWrapper_qtquick.cpp

@@ -64,7 +64,12 @@ void ViewWrapper_qtquick::setGeometry(QRect)
 {
 }
 
-QWindow *ViewWrapper_qtquick::windowHandle() const
+std::shared_ptr<ViewWrapper> ViewWrapper_qtquick::childViewAt(QPoint) const
+{
+    return {};
+}
+
+std::shared_ptr<Window> ViewWrapper_qtquick::windowHandle() const
 {
     return {};
 }
@@ -100,6 +105,11 @@ bool ViewWrapper_qtquick::isMaximized() const
     return {};
 }
 
+bool ViewWrapper_qtquick::isMinimized() const
+{
+    return {};
+}
+
 QSize ViewWrapper_qtquick::maximumSize() const
 {
     return {};