Add localized strings and icons for artifact types

[SteveLasker]

Capture how artifact authors can provide localized strings and logos for how their artifact can be visualized in registry specific tooling. This surfaces the details captured here: https://github.com/opencontainers/artifacts/blob/f9710ad60b6de311843df88d8f8fa1e6d0d44b50/authoring-artifacts.md#optional-publishing-the-artifact-type