Add OCI Source Image Mime Type to defaults in Quay

With 3.6.0 support for custom OCI mime types, we should also add the following type to support source containers- this will be important when we re-base quay.io so that RH can use it to hold source containers.

{
  "schemaVersion": 2,
  "config":

{     "mediaType": "*application/vnd.oci.source.image.config.v1+json*",     "digest": "sha256:4abb592db45b727aa2ba0b0740efe62cfc26f4aa0bf8d4cc0022a25837ec6952",     "size": 49   }

,
  "layers": ...
}

Lets add this to both Quay's internal default as well as ConfigTool.

 

Acceptance Criteria:

• For context source images are created using buildah:
  • buildah source create new-source-image && buildah source add new-source-image path/to/repository
• Must be able to push source images to quay with mime type of `application/vnd.oci.source.image.config.v1+json`
  • Ex. buildah source push new-source-image localhost:8080/admin/new-source-image:latest
• Must be able to pull images of mime type `application/vnd.oci.source.image.config.v1+json` using buildah
  • Ex. buildah source pull localhost:8080/admin/new-source-image:latest