DeepImpact implementation

[amallia]

I would love to see DeepImpact (https://arxiv.org/pdf/2104.12016.pdf) here.

[raphaelsty]

Hi @amallia, that would be very relevant. If you're interested in developping it, any contribution is welcome. Once I have more time, I'll study this :) The code would rely on Hugging Face Transformers tooling as much as possible with some Pytorch in order to train and run inference with the model.