[Misc] Add BNB quantization for Whisper

[jeejeelee]

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[github-actions]

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[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @jeejeelee.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[mgoin]

Sorry for the delay, this looks good to me! Will this work with a weight load test from a prequantized checkpoint?

[jeejeelee]

Sorry for the delay, this looks good to me! Will this work with a weight load test from a prequantized checkpoint?

I have tested both online and offline quantization locally, and both were able to generate reasonable results