Add more audio models: ast, hubert, unispeech, unispeech-sat, wavlm

[JingyaHuang]

What does this PR do?

Add more audio models based on our support for wav2vec2.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you make sure to update the documentation with your changes?
• Did you write any new necessary tests?

[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.

[dacorvo]

Nice, thanks !