Removes the previous `AppIcon.appiconset` bundle and replaces it with
all of the necessary asset slices to enable all of the Liquid Glass
variants of the app icon on iOS 26, while also preserving backwards
compatibility with older iOS versions.
<img width="1164" height="388" alt="LiquidGlass"
src="https://github.com/user-attachments/assets/7d6e7a90-3fe5-4853-9c63-35144359f49e"
/>
---------
Co-authored-by: Dean Herbert <pe@ppy.sh>
Note that the NativeLibs package required by osu.Framework includes assemblies that will not link on Xamarin.iOS. For now we explicitly reference the package and exclude all assets, and manually provide the BASS libraries.