Documents: 
https://docs.openshift.com/container-platform/4.10/security/compliance_operator/compliance-operator-installation.html
https://docs.openshift.com/container-platform/4.12/security/compliance_operator/compliance-operator-installation.html

It would be nice to have a warning/important box on the Installation pages (similar to the one in https://docs.openshift.com/container-platform/4.12/security/compliance_operator/compliance-operator-supported-profiles.html) that warn the readers that at the moment Compliance Operator is not supported on ARO. Maybe it's a good idea to point to the KCS that was written --> https://access.redhat.com/solutions/7002713

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