[xcode11-feature] Swift Libraries (CryptoKit and RealityKit)

Both [CryptoKit](https://developer.apple.com/documentation/cryptokit) and [RealityKit](https://developer.apple.com/documentation/realitykit) are Swift-only, with no Objective-C binding.

Infrastructure to work on swift is in work but not public currently.

If we wish to support these libraries, we need to figure out what shipping a Swift library binding truly entails.

> As a friendly reminder, an issue card is not a guarantee that a certain feature will be done, or done under any particular time frame. Issues allow us to document what features we do and do not have, and give the community a place to provide feedback.