Added camera type to callback when a photo is taken

[KaneCheshire]

This PR adds support for providing the camera device / type of camera that took a photo (i.e either front or rear facing camera).

An associated value is added to the PhotosInputViewPhotoSource.camera case, with a value of a newly added CameraType enum type (eitherr front or rear.

This shouldn't be a breaking change for consumers of the API because you can still do:

switch source {
case .gallery: break
case .camera: break
}

But now you can also do:

switch source {
case .gallery: break
case let .camera(cameraType): break
}