[Feature] Advanced navigation method: GoBack

[BurkusCat]

Is your feature request related to a problem? Please describe.
.Pop when called on the final page does not close the app. I want a way to close the app if I am navigating back on the final page.

Describe the solution you'd like
.GoBack method that functions the same as .Pop except it closes the app on the final page.

Describe alternatives you've considered
Manually calling close app myself

Proposed APIs
If possible, try to propose how the API might look. For example:

// INavigationService
Task GoBack();

Task GoBack(NavigationParameters navigationParameters);

Additional context
Needs added to Burkus' BackButtonNavigator.