NEXUS-4372: Cleanup

Getting rid of unused imports, warnings etc
Making the "smoke IT" pass

Until Alin does not returns from his
love romance and reveals how to get the Nexus
version from IT.
NEXUS-5472: WL DTOs must be registered globally

To allow Client to use them too.
Renamed "smoke" IT
NEXUS-5472: Whitelist ITs WIP

For now, two simple tests, one "smoke" and one
slow