Add Fast Image Processor for Idefics3
Author: rootonchair
Pull request: yes

# What does this PR do?

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Related #36978


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> Hi @rootonchair , thanks for contributing this, overall looks really good! There is an ongoing discussion on what to do with Lanczos resampling, but in the meantime I'm curious what diff you get with Bicubic when testing against the slow processor (using Lanczos) in `test_slow_fast_equivalence` and `test_slow_fast_equivalence`?

@yonigozlan thanks for your thorough reviews. So I did a benchmark that measures MAE between LANCZOS and other resamplers. As you can see, BICUBIC is the most suitable approximation among others

| Fast resampler| `test_slow_fast_equivalence`  | `test_slow_fast_equivalence_batched` |
| ------------- | ------------- | -------------|
| BICUBIC  |  0.018636604771018028 | 0.05995668098330498
| BILINEAR  | 0.05067451298236847  |  0.13565397262573242
| NEAREST | 0.2290235459804535 | 0.5087724924087524

> @yonigozlan thanks for your thorough reviews. So I did a benchmark that measures MAE between LANCZOS and other resamplers. As you can see, BICUBIC is the most suitable approximation among others

Very cool, thanks for that. Looks like Bicubic is the way to go indeed. It's not ideal to have non negligeable differences in the processing, but I guess it's the best we can do for now.