Add ServiceCollection extensions for native Android and iOS projects

### Problem Statement

For projecs not using the MAUI UI framework and not relying on its MauiAppBuilder it would be nice to have extensions to set up in a net?-android and net?-ios App.

### Solution Brainstorm

I guess the main issue here would be to have to hook into lifecycle events yourself, instead of relying on the interfaces MAUI framework provides. But it would behave exactly the same as a native Android and iOS App would.