Add keycloak postgres container image SHA to the operator deployment

gistfile1.txt

1. Mirror registry.access.redhat.com/rhscl/postgresql-10-rhel7@sha256:c90309cc7c5a039654b81c8d1b6aebfd447578841a61bf4d5530e7a927d5a832 internally
2. Configure an ImageContentSourcePolicy if not already done
3. Add the RELATED_IMAGE_POSTGRESQL to the rhsso-operator via the rhsso-operator CSV

$ oc edit csv -n openshift-mta rhsso-operator.7.6.1-opr-005  
  
  install:
    spec:
      deployments:
      - name: rhsso-operator
        spec:
          replicas: 1
          selector:
            matchLabels:
              name: rhsso-operator
          strategy: {}
          template:
            metadata:
              labels:
                name: rhsso-operator
            spec:
              containers:
              - env:
                - name: RELATED_IMAGE_POSTGRESQL
                  value: registry.access.redhat.com/rhscl/postgresql-10-rhel7@sha256:c90309cc7c5a039654b81c8d1b6aebfd447578841a61bf4d5530e7a927d5a832
...