Improve the Relax frontend interface for PyTorch-exported ONNX frontend models

[xinetzone]

see: [Bug] relax ONNX Resize operator conversion with opset_version=11 is unsupported

[Hzfengsy]

Would be great if you could decouple the torch expoert and onnx.

To be specific, could you pleease craft the ONNX model directly, instead of exporting from pytorch

[xinetzone]

@Hzfengsy Remove PyTorch dependencies

[Hzfengsy]

Please:

1. fix CI, including lint and import error
2. merge the test tests/python/relax/test_frontend_onnx_resize.py into tests/python/relax/test_frontend_onnx.py
3. Not sure if tests/python/relax/test_frontend_torch_onnx_export.py is still needed. If not, please remove it

[xinetzone]

@Hzfengsy Resubmission

[Hzfengsy]

Please fix the ci

[xinetzone]

@Hzfengsy I don't know how to fix the CI.