Create different UITest types

[eonist]

enum UITestType {
   case basics // Covers the basics
   case comprehensive // Covers everything
   case mixAndMatch // Runs different scenes in random order
   case repeating(type: Self, count: Int) // Can repeat a test n-times
}
extension UITestType {
   var scenes: Scenes {
      switch self {
         case basics: return []
         ...
      }
   }
}