Add a Classpath Duplicate JAR Detector Unit Test

[vorburger]

http://blog2.vorburger.ch/2019/02/how-to-find-duplicate-classes-and.html

https://github.com/classgraph/classgraph/issues/256

https://javadocs.opendaylight.org/org.opendaylight.infrautils/sodium/org/opendaylight/infrautils/testutils/ClasspathHellDuplicatesCheckRule.html

https://issues.apache.org/jira/browse/FINERACT-919

https://github.com/apache/fineract/pull/803/files

@jingtang10 @omarismail94 this is to track what we chat about earlier today; I'll see if I can add this here, some time.