MoveContentEventArgs.ContentLink should be updated when content is moved between providers

Description

When a content item is moved between content providers, the ContentLink for the content provider should change. However, the property MoveContentEventArgs.ContentLink is never updated, so an event handler that tries to load the content using args.ContentLink faces a ContentNotFoundException.

Breaking change
Update eventArgs.ContentLink when moving between providers (as we do with args.Content), there is a property MoveContentEventArgs.OriginalContentLink that holds the "old" reference.