Making VQ training ready

[adefossez]

Checklist

• [x ] Read CONTRIBUTING.md, and accept the CLA by including the provided snippet. We will not accept PR without this.
• [ x] Run pre-commit hook.
• If you changed Rust code, run cargo check, cargo clippy, cargo test.

PR Description

VQ in the initial release didn't contain the code for the training, now it does!

[LaurentMazare]

Looks good, thanks!