Enhance MoveBranchRequest to take a new name, analogous to how CopyBranchRequest works

CopyBranchRequest has a desiredNameForCopy that is used to specify the name for the new copy, which may be null if the original name is to be used. MoveBranchRequest should also have a desiredNewName that, if provided, would also rename the node.

This change will affect all of the existing connectors that support updates, but it does close a gap in the Graph functionality.