Provide a NavigatorObserver to track navigations

[SametSahin10]

Summary

In order to track navigations, a NavigatorObserver is used on Flutter but I've noticed that there isn't a NavigatorObserver provided by this package. Could we create a NavigatorObserver that observes navigations and tracks them using Amplitude? Check out this code in flutter-segment repo for an example.

Motivations

Providing a NavigatorObserver to track navigations using Amplitude.

[chillbrodev]

Is there an update on this feature? It is an important piece for analytics. FirebaseAnalytics and other Analytic platforms have this feature.