[Pipeline] Marigold depth and normals estimation

[toshas]

What does this PR do?

Fixes #7522.
Related to #6533 (community pipeline).

This PR adds the family of Marigold pipelines for dense regression tasks. The depth estimation pipeline is largely an improved version of the community pipeline. The new normals estimation pipeline adds a new functionality of computing surface normals.

Before submitting

• Did you read the contributor guideline?
• Did you read our philosophy doc (important for complex PRs)?
• Was this discussed/approved via a GitHub issue or the forum? Please add a link to it if that's the case.
  move MarigoldPipeline to core  #7522
  Marigold - monocular depth estimation pipeline #6533
• Did you make sure to update the documentation with your changes? Here are the documentation guidelines, and here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

@sayakpaul @yiyixuxu

[sayakpaul]

Thanks a lot for working on this. I did a pass through the depth estimation pipeline implementation and left some comments regarding the overall design, some nits, and other things.

I'd wait for @yiyixuxu to review as well before making any changes.

[yiyixuxu]

thanks for the PR
i left some feedbacks! I agree with all the @sayakpaul 's comments too but I think we should first address the denosing loop, it is very hard to understand what's actually going on right now

[toshas]

The documentation currently pulls files from the unmerged PRs here:
https://huggingface.co/datasets/huggingface/documentation-images/discussions/338
https://huggingface.co/datasets/huggingface/documentation-images/discussions/339
https://huggingface.co/datasets/huggingface/documentation-images/discussions/340

Once these are merged, paths to images will need to be updated again

[sayakpaul]

Thanks for the doc related changes.

My main comments are:

• Let's keep the API docs super lightweight.
• All the additional details provided can be repurposed as a guide like https://huggingface.co/docs/diffusers/main/en/using-diffusers/svd.

So, let's proceed with this plan?

[toshas]

Hi @sayakpaul , I made a round of changes, please let me know what you think about the new separation of the documentation!

[sayakpaul]

Let's remove the unrelated changes in the toc and then we can merge this!

[sayakpaul]

Thanks a mile for landing this one with such poise and greatness, @toshas!

[toshas]

Thanks, @sayakpaul and @yiyixuxu, for guiding me on this one, It was an amazing experience, and I am very happy with the result!