Add DePlot + MatCha on `transformers`
# What does this PR do?

Adds [MatCha](https://arxiv.org/pdf/2303.18223.pdf) and [DePlot](https://arxiv.org/pdf/2212.10505.pdf) on `transformers`. 
Those are two different papers from Google AI but fully based on `Pix2Struct`. 

Model weights: 

- https://huggingface.co/ybelkada/deplot
- https://huggingface.co/ybelkada/matcha-base
- https://huggingface.co/ybelkada/matcha-chart2text-pew
- https://huggingface.co/ybelkada/matcha-chart2text-statista
- https://huggingface.co/ybelkada/matcha-plotqa-v1
- https://huggingface.co/ybelkada/matcha-plotqa-v2

I will move them to Google org once I will double check the model card contents with the authors

EDIT: all the weights have been moved


_The documentation is not available anymore as the PR was closed or merged._<|||||>All models have been moved to Google org and model cards updated correctly! This PR is ready for review cc @sgugger 