Add recipebrowser example

The example uses WebEngineView and Qt Quick Controls 2 items to
demonstrate how to write a small hybrid QtQuick / HTML application,
and also shows the usage of the new focusOnNavigationEnabled setting.

Task-number: QTBUG-52999
Change-Id: I1813a658a2f46e90f9ca4e8229a8c8fbb6590248
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>
Reviewed-by: Michal Klocek <michal.klocek@qt.io>