Add spleeter (CLA demo)

[Holzhaus]

No description provided.

[github-actions]

CLA Assistant Lite bot:
Thank you for your submission, we really appreciate it. Like many open-source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution. You can sign the CLA by just posting a Pull Request Comment same as the below format.

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I have read the CLA Document and I hereby sign the CLA

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0 out of 2 committers have signed the CLA.
❌ @katsar0v
❌ @Holzhaus
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