feat: add device id

[michaelfeil]

What does this PR do?

This adds a option to the CLI to select the device ID.

Fixes # (issue)

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline?
• Was this discussed/approved via a GitHub issue or the forum? Please add a link to it if that's the case.
• Did you make sure to update the documentation with your changes? Here are the documentation guidelines.
• Did you write any new necessary tests? If applicable, did you include or update the insta snapshots?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

[OlivierDehaene]

Why not use the CUDA_VISIBLE_DEVICES env var?

[michaelfeil]

@OlivierDehaene good to see you. I actually want to add py03 bindings for the backend, and wiring that though would help. Env vars can't change, so its more about adding this capability into backend.

[alvarobartt]

Thank you @michaelfeil, I've left some comments!

P.S. Agree with @OlivierDehaene that using CUDA_VISIBLE_DEVICES would be ideal, but given that this might help with your use-case it's probably the same with other users, so I'm happy to move forward, unless Olivier thinks otherwise, I don't have a strong opinion against this change 🤗

[michaelfeil]

@alvarobartt