Rework MvxNavigationService

[Cheesebaron]

The idea behind MvxNavigationService is great. However, the fact that we are using annotations, which create instances of ViewControllers/Fragments/Activities just to look up how to navigate is a huge downside.
Along with that, plus the fact that it is hard to figure out how the navigation tree looks like of the App.

It would be nice to reconceptualize or build further upon the routing navigation that was added on top.

There are also a lot we can do with regards to navigation on various platforms that could be improved significantly, such as Fragment navigation and supporting a lot of the modern functionality that we now have on Android, such as shared transitions, proper control of how Fragments are transacted upon etc.

[qwertylolman]

i think, ViewModel lifecycle should be redesigned as well. ViewModel should be inside the context of the page (VC/Activity/Fragment/etc). like in the native Android. so navigation will appear between abstract pages, and not between ViewModels