Exporters onnx module (#403)
* [WIP] ONNX export in optimum => Bert works
* [WIP] ONNX export in optimum => GPT-2 / GPT Neo
* [WIP] ONNX export in optimum => T5
* [WIP] ONNX export in optimum
* [WIP] Add support for TensorFlow export
* [WIP] onnx export
* Update file headers
* [WIP] cache features.py
* Refactor features.py
* Bert like models ready
* Apply suggestions
* Clean up
* Backup input_generators.py version
* Most seq2seq models work
* Add vision models
* Support for GPT-J
* CLIP is working
* Add support for the remaining models
* Make style
* Fix workflow and remove commented code
* nit
* Renamed dynamic axes
* Fix BART
* Drop support for PyTorch 1.10 and lower
* Add re-order inputs method
* Small fixes
* Changed FeaturesManager to TasksManager
* Apply suggestions
* Fix Bloom export
* Fix mt5 export
* Change ATOL_FOR_VALIDATION for ResNet
* Update github actions for exporters to use pytest
* Styling
* Remove old comment
* Fix github action for exporters
* Fix tests that are not passing
* Styling
* Change Blenderbot model to use
* Change Resnet ATOL value
