REST extensions for the Qt Widget Address Book example

The current Address Book example (https://doc.qt.io/qt-6/qtwidgets-itemviews-addressbook-example.html) is based on Qt Widgets and uses a proxy model to provide different views on the data. The goal for this epic is to use this example to explore, review and extend Qt for better use in networked scenarios. This epic will include a rage of tasks and user stories for other components in Qt in addition to the Address Book example if needed.