Add a SwiftUI example to Revert

[orj]

With the introduction of SwiftUI in iOS 13 Revert should have an example of this sort of view hierarchy so to ensure that Reveal renders information accurately.

Cases test:

• Hosting SwiftUI in a primarily UIKit view hierarchy (eg, a nested UIHostingViewController).
• Hosting UIKit views and controllers in in a primarily SwiftUI view hierarchy (adopting UIViewRepresentable and UIViewControllerRepresentable).