Image pull per runtime class

Today, container images in container runtimes are identified by the image name (aka. image reference) and/or image digest (usually a SHA256 cryptographic hash of the content). The content of the image referenced is either an image manifest or an image index manifest. The image index is typically arranged to contain a list of image manifests by platform (linux, windows,...). When the reference is to an image index, platform matching logic is used to identify and pull the appropriately matching image manifest from the index for the platform that the container is being asked to run on. <pre> Example of an index image, Python: { "schemaVersion": 2, "mediaType": "application/vnd.docker.distribution.manifest.list.v2+json", "manifests": [ { "mediaType": "application/vnd.docker.distribution.manifest.v2+json", "size": 2007, "digest": "sha256:8a164692c20c8f51986d25c16caa6bf03bde14e4b6e6a4c06b5437d5620cc96c", "platform": { "architecture": "amd64", "os": "linux" } }, { "mediaType": "application/vnd.docker.distribution.manifest.v2+json", "size": 2007, "digest": "sha256:ceac4b5b55ccba7b742e0a2d2765711c44cd228d1a990018a07b94b48c59577e", "platform": { "architecture": "arm", "os": "linux", "variant": "v5" } }, { "mediaType": "application/vnd.docker.distribution.manifest.v2+json", "size": 2007, "digest": "sha256:ea4f4ff16827bdc8e019284f964a397968c3769cc6534502009ff9516bd8c4f4", "platform": { "architecture": "arm", "os": "linux", "variant": "v7" } }, { "mediaType": "application/vnd.docker.distribution.manifest.v2+json", "size": 2007, "digest": "sha256:20d0d27bf4b7998f6deaa523de3f5dd5298d7b53e7e02adccb9b7df183b638c2", "platform": { "architecture": "arm64",