Improve DCN handling during domain creation
Current due to most likely concurrent operations exceptions are being thrown during domain creation.
2024-03-14 08:11:51,526 [askExecutor-962] INFO trators.kubernetes.KubernetesNamespaceManager: 84 - < trigger
Exception in thread "SimpleAsyncTaskExecutor-966" net.geant.nmaas.orchestration.exceptions.InvalidDomainException: llopatt1
at net.geant.nmaas.dcn.deployment.DcnRepositoryManager.lambda$loadDcnOrThrowException$2(DcnRepositoryManager.java:76)
at java.base/java.util.Optional.orElseThrow(Unknown Source)
at net.geant.nmaas.dcn.deployment.DcnRepositoryManager.loadDcnOrThrowException(DcnRepositoryManager.java:76)