qtquick: Move the example into a sub-directory

We'll have other qtquick examples

examples/qtquick/dockwidgets/main.qml

@@ -0,0 +1,23 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2020 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+  Author: Sergio Martins <sergio.martins@kdab.com>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <info@kdab.com> for commercial licensing options.
+*/
+
+import QtQuick 2.6
+import com.kdab.dockwidgets 1.0 as KDDW
+
+KDDW.MainWindow {
+    id: root
+
+
+    Component.onCompleted: {
+        root.init("MyWindowName-1");
+    }
+}
+