Problem Description: 

1. Use `pulpcore-manager add-signing-service` to create a [`rpm-sign`](https://docs.engineering.redhat.com/display/PRODSEC/Signing+Server+User+Guide#SigningServerUserGuide-2.GoldandContainerReadyKeySigning) based signing service
2. And configure `settings.COLLECTION_SIGNING_SERVICE` pointing to that service also enable it to be used on the certitication process.

QA Criteria: 

• All content served on CAH must be signed using a redhat certified key