Rewrite of `certifyToscaElement` to remove NPE
- Modularized `certifyToscaElement` in smaller, less complex methods (`handleRelationsBeforeCertifyingAndProcessClone`, `cloneToscaElementAndHandleRelations`, `handleRelationsOfNewestCertifiedToscaElementAndReturn` & `logDebugMessageAndReturnStorageOperationStatus`)
- Removed potential NPE flagged by Sonar in `certifyToscaElement`
Issue-ID: SDC-2966
Signed-off-by: Chris Andre <chris.andre@yoppworks.com>
Change-Id: Id65871cbfd611abdcc878e61c1541f01ff972828