Say hello to more customization options

It's another major update but it shouldn't lead to a breaking change.

New

• Support for a custom RemoteImageURLDataPublisher (by default: URLSession.shared)
  --> Now you can use your custom URLSession, for example with low data mode support
• Use the new SwiftUI StateObject property wrapper with your service instance, just pass it to the new initializer with the service parameter (create an instance of the built-in service through the DefaultRemoteImageServiceFactory)
• Support for a custom RemoteImageService
  --> Customize the service completely to your needs
  --> Prefetch images if you want

Improvements

• Optimizations under the hood
• Added some basic API documentation

Other

• RemoteImageType phAsset is now deprecated (will be removed in the future) because the localIdentifier is device specific and therefore cannot be used to uniquely identify a PHAsset across devices.