[Modular] Add single file support to Modular

[DN6]

What does this PR do?

This PR

1. Adds support for single file loading in ComponentSpec

2. Renames the repo argument to pretrained_model_name_or_path. IMO this makes more sense if the same argument supports both filepath and repo_ids. Saw that there was a comment in there considering this chase, so I added it here. Alternatively, we can introduce a filename argument, but I this is cleaner.

Snippet to test

import torch
from diffusers.modular_pipelines.modular_pipeline_utils import ComponentSpec
from diffusers import FluxTransformer2DModel

component = ComponentSpec(
    "transformer",
    pretrained_model_name_or_path="https://huggingface.co/black-forest-labs/FLUX.1-dev/blob/main/flux1-dev.safetensors",
    type_hint=FluxTransformer2DModel
)
model = component.load(torch_dtype=torch.bfloat16)

Fixes # (issue)

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• 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.
• 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?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[DN6]

@bot /style

[github-actions]

Style bot fixed some files and pushed the changes.

[yiyixuxu]

thanks!

[DN6]

@yiyixuxu Since there are some public models using modular thought it would be better to deprecate repo. Would you mind taking another look here please 🙏🏽

[yiyixuxu]

thanks! change looks good to me
I will run more slow tests later, but good to merge as long as you test out the public repo (krea) and make sure it works there