Investigate: How to correctly handle multi-arch images

Context

As part of &10434 (closed), we need first to conduct an investigation to build out an implementation plan.

Problem to solve

Currently, the container registry UI has limited support for displaying manifest lists. A manifest list is an index for multiple related images/manifests. These are most commonly used for multi-arch images, indexing platform-specific image variants for a given piece of software.

Proposal

Investigate the problem and identify an implementation plan to ensure that multi-arch images are handled correctly in the GitLab Container Registry, UI, and API.