Add OCI annotations to manifests and indexes

[AustinAbro321]

Is your feature request related to a problem? Please describe.

With the introduction of the v1beta1 schema we will deprecate several of these metadata fields in favor of an annotation field - #2636. Currently, annotations can be seen from a manifest config, check out the init package manifest config. To make it easier to consume annotations they should be added to both the OCI manifest and index.

Describe alternatives you've considered

We could keep them only on the manifest config or the zarf.yaml file, but since this is a low cost way to give more info on the image this seems beneficial.

[marshall007]

Related to #3009. We should also pull annotations from the blobs into layers when the layer is a well-defined OCI mediaType (like an image index/manifest).