Merge MediaGallery and Permission packages

[beeradmoore]

Summary

There may be a very good reason for this, but I don't understand why there is a base Xamarin.MediaGallery package, and then also Xamarin.MediaGallery.Permision and Xamarin.MediaGallery.Permision.Maui packages.

I first thought it was so you wouldn't have to take on a dependency of Xamarin.Essentials but it appears that both Xamarin.Essentials and Xamarin.MediaGallery.Permission* are dependencies of Xamarin.MediaGallery (at least that's how it looks according to this.

I think removing it as a seperate project may simplify things a tad. If you are ok with this I can make the change on a branch that I have which is a branch off feature/custom_albums where I have done some project organisation updates (uncommitted currently).

API Changes

Deprecate Xamarin.MediaGallery.Permision nuget package. Deprecate Xamarin.MediaGallery.Permision.Maui nuget package. All code references should work fine as they use the root namespace of NativeMedia. If people have these additional nugets installed manually they will have to remove them which may be considered a breaking change but I can make sure its documented.