NEXUS-6479: Unifying and cleaning up realm names and user source names
NEXUS-6479: Renamed IT constants

that were left as dangling after few reshuffles
NEXUS-6479: More test cleanup

As CI caught one place, but it turn out
there are more hints littered across tests
as plain string literals.
NEXUS-6479: Another literal.
NEXUS-6479: Renamed abstract realm
Merge pull request #575 from sonatype/nexus-2.9.x-NEXUS-6479-naming-discrepancy

REVIEW [2.9] NEXUS-6479: LDAP naming discrepancy