onnxruntime

Graph transformer to ensure unique DQ nodes for QDQ node units (#15145)

### Description
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Add required graph transformer to duplicate DQ nodes to ensure that QDQ
node units have unique DQ nodes. This condition is necessary for QDQ
node unit processing.

### Motivation and Context
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- If it fixes an open issue, please link to the issue here. -->

There is an existing Python utility that does this: 

https://github.com/microsoft/onnxruntime/blob/c7ced7a5e9c5ba1245b03f84edd537f45432b2e9/tools/python/util/qdq_helpers/qdq_model_utils.py#L77

This PR implements it as a graph transformer so it is integrated into
ORT and does not require a separate step to update the model. There are
also tests to ensure that its effects are not undone by basic level
graph optimizations.