Create process to automatically generate AndroidManifest.xml attributes

[jpobst]

Context: #8235

New API levels often add new AndroidManifest.xml elements that can be specified. We make these available to users as C# attributes, eg: [IntentFilter].

This requires updates to multiple files:
‎src/Mono.Android/Android.App/IntentFilterAttribute.cs
src/Xamarin.Android.Build.Tasks/Mono.Android/IntentFilterAttribute.Partial.cs

We have a script we can manually run to find any new manifest elements:
https://github.com/xamarin/xamarin-android/tree/main/build-tools/manifest-attribute-codegen

However, making the code changes is tedious and potentially error prone. It would be nice if we had a script we could run that would also automatically generate the needed code changes.

Example change:
#8261

Additionally there is some discussion about this process and undocumented attributes here: #1336

Related issue: #8729