Add a custom service account for apicurio registry.

[jhughes24816]

Pods should refer to a ServiceAccount other than "default" at spec.serviceAccountName. The default ServiceAccount grants many permissions that likely are not needed by the Pod and may not match the required needs of the workload. The "default" may have higher or lower permissions than what is required and can also change over time, impacting the operations of the workload.

Proposed solution: the operator builds a service account with the same name as the registry instance and sets it up with the correct initial permissions.