Update samples to use Jetpack Window Manager stable

[conceptdev]

Window Manager is an API that provides information about dual-screen and foldable display features, that work not just for Surface Duo but also devices from other OEMs.

There is a pre-release binding available on NuGet - Xamarin.AndroidX.Window - which has been implemented in the Xamarin.Android samples in this repo.

We've our updated docs and blog.

Pre-requisites

This issue relies on Google releasing the stable version of Jetpack Window Manager.

Google reference

There is documentation, a blog post, and a codelab on how to use it in Kotlin.

Xamarin.Forms

This applies to the Xamarin.Android samples in this repo. The Xamarin.Forms samples will require Window Manager to be incorporated into the Xamarin.Forms.DualScreen NuGet package, which is a separate task.