We need to expose NovaExternalCompute.Spec.CustomServiceConfig to the end user via the OpenStackDataPlaneNode CRD. We probably need a NovaExternalComputeTemplate struct defined there with all the fields that is expected to be defined by the end user.
as part of this we should ensure the NovaExternalCompute cr is only created if NovaExternalComputeTemplate is species with the required fields. (the minium required filed is the cell name)