Adding support for `array` key in raw dictionnaries in ASR pipeline.
Author: Narsil
Pull request: yes

# What does this PR do?

Adding support for `array` key in raw dictionnaries in ASR pipeline.
This means we can simplify the Quicktour example to look again a bit
more what the old `ffmpeg` example looked like.

Even simpler code might be enabled by
https://github.com/huggingface/datasets/issues/4180
in the future. We could then remove the `[:4]` which is currently necessary to prevent
loading a huge audio in RAM upfront.

Performance-wise the iterator also enables using stuff like `batch_size` and `num_workers` in the
pipeline object to get optimal performance (this will only show real differences on GPU which is not
included in this quicktour)

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Fixes # (issue)


## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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- [ ] Did you write any new necessary tests?


## Who can review?

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members/contributors who may be interested in your PR.

@patrickvonplaten
@sgugger

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Comments:
_The documentation is not available anymore as the PR was closed or merged._