feat(gpu): add support for a custom device selection on multi-gpu mode

[pdroalves]

closes: https://github.com/zama-ai/tfhe-rs-internal/issues/960

PR content/description

Check-list:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• Relevant issues are marked as resolved/closed, related issues are linked in the description
• Check for breaking changes (including serialization changes) and add them to commit message following the conventional commit specification

[tmontaigu]

The custom case in the CudaStreamPools is not able to handle all possible cases but for now it should be enough

[agnesLeroy]

Awesome @pdroalves, looks good to me!