Until we have some experience hosting foreign layer manifests, the Hub
operators wish to limit foreign layers on Hub. To that end, this change
adds registry configuration options to restrict the URLs that may appear
in pushed manifests.
Signed-off-by: Noah Treuhaft <noah.treuhaft@docker.com>
Create signedManifestHandler and schema2ManifestHandler. Use these to
unmarshal and put the respective types of manifests from manifestStore.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>