OnnxLabelScorer under Onnx or Nn?

[NurAd-Din]

I was wondering where you think the new OnnxLabelScorer would have to be. The TFLabelScorer was not under Tensorflow but under Nn so there's a case to be made that maybe the new label scorer should also be under Nn instead of Onnx. In the meantime I've placed it under Onnx but I'll wait for your feedback for a definitive decision.