No way to be notified upon creation of a new widget instance with specified widgetGuid

[dfinkbeiner]

The class Ozone.state.WidgetState allows you to add state event listeners for a plethora of state events - but everything is tied to a widget's instanceId. There needs to be an API where you can provide a widgetGuid and receive callback when an instance of a widget with that widgetGuid is created. The callback should pass a state object with the same properties that Ozone.state.WidgetState.getWidgetState.cfg.callback provides. The callback should be called anytime a widget with that widgetGuid is created - regardless of whether it's caused by the user using the Launcher to create a new instance of that widget or whether the user just logged in and OWF is restoring his dashboard to how it was when he last logged out.