Undocumented `enableCertManager` value is required

[chipzoller]

There is an undocumented value discovered here called enableCertManager which must be set to true, at least when installing NCO outside of an OpenShift environment, as well as a prerequisite that cert-manager be installed, in order to provision the certs necessary to start the NCO deployment. Without these, the Pod will not start because the Secrets namespace-configuration-operator-certs and webhook-server-cert will not be created, which are mounted as volumes.

README should be updated to state for deployment at least outside of an OpenShift environment:

• Cert-manager is required
• Pass the value enableCertManager: true in order to provision the necessary certificate-related resources

[raffaelespazzoli]

hey would you be so kind to contribute this documentation change?