feat: allow saving specific platforms for an image

[LaurentGoderre]

What does this PR do?

This introduces a way to pass image save options (like platform) to the image client. This allows saving a specific architecture for an image.

Why is it important?

With OCI multi-arch images, it is sometimes needed to save image for a different architecture than the current one. This changes allows to control the behavior instead of defaulting to the current platform.