Add config for generating ONNX models for table-transformers

[antew]

What does this PR do?

Allows generating ONNX models for table-transformers.

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Who can review?

@NielsRogge - This adds a small bit on top of the work you did in #19614 to allow generating ONNX models for table transfomers (e.g. python -m transformers.onnx --model="microsoft/table-transformer-structure-recognition" table/)

Without this addition, I was getting this error:

KeyError: "table-transformer is not supported yet.
Only ['albert', 'bart', 'beit', 'bert', 'big-bird', 'bigbird-pegasus', 'blenderbot', 'blenderbot-small', 'bloom', 'camembert', 'clip', 'codegen', 'convbert', 'convnext', 'data2vec-text', 'data2vec-vision', 'deberta', 'deberta-v2', 'deit', 'detr', 'distilbert', 'electra', 'flaubert', 'gpt2', 'gptj', 'gpt-neo', 'groupvit', 'ibert', 'imagegpt', 'layoutlm', 'layoutlmv3', 'levit', 'longt5', 'longformer', 'marian', 'mbart', 'mobilebert', 'mobilenet_v1', 'mobilenet_v2', 'mobilevit', 'mt5', 'm2m-100', 'owlvit', 'perceiver', 'resnet', 'roberta', 'roformer', 'segformer', 'squeezebert', 'swin', 't5', 'vision-encoder-decoder', 'vit', 'whisper', 'xlm', 'xlm-roberta', 'yolos'] 
are supported. If you want to support table-transformer please propose a PR or open up an issue.

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint.

[sgugger]

Note that we don't accept new model exports in Transformers, as we moved that part into the Optimum library. You should open a PR to add support there :-)

[antew]

Note that we don't accept new model exports in Transformers, as we moved that part into the Optimum library. You should open a PR to add support there :-)

Thank you @sgugger, will do!