[ONNX] Design ONNX exporter errors

[justinchuby]

A lot of times the onnx exporter raises Runtime errors. We can design better classes of errors to surface the right/actionable information to users.

Unsupported ops

Current behavior

torch.onnx.symbolic_registry.UnsupportedOperatorError: Exporting the operator prim::DictConstruct to ONNX opset version 14 is not supported. Please feel free to request support or submit a pull request on PyTorch GitHub.

What may be useful for users

1. Whether it is supported in other opset versions
2. Where and how to request support

Quantized op

• [ONNX] Improve quantization error message #81566

Runtime error during symbolic conversion

• Context can be included to aid troubleshooting