[ONNX] Add Internal Utils: onnx_proto_utils.py for onnx/onnx-script/onnx_proto (#88376)
Added `onnx_proto_utils.py` for onnx/onnx-script related process. The idea is like jit_utils.py, and to simplify what we have in `torch/onnx/utils.py`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/88376
Approved by: https://github.com/justinchuby, https://github.com/BowenBao
