Add Fast Conditional-DETR Processor

[keetrap]

Related #36978
cc @yonigozlan

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[yonigozlan]

Hi @keetrap, before I dive deep into the code, could you check if it would be useful to use modular here, as this image processor seems to have some similarities with other DETR image processors? You can look at the modular files of Deformable DETR and RT DETR to see how it's done. Thanks for working on this!

[keetrap]

@yonigozlan Thanks for the review. I’ve added the modular file. The tests are failing here, but they’re passing locally.

[yonigozlan]

Thanks looks great @keetrap , last thing to do is make sure that both classes are tested in all image processing tests

[yonigozlan]

Thanks for making the changes! LGTM, but let's wait for @ArthurZucker final approval before