JAVA-17: Methods expecting 'single result' in JPAPersistenceService should return null when no result is found instead of NoResultException
Merge branch 'feature/JAVA-17' into develop

Conflicts:
	framework/modules/backend/core/persistence/eclipselink/src/test/java/org/appverse/web/framework/backend/persistence/services/integration/impl/test/UserRepositoryImplTest.java