Solve the problem of cross-system integration tests

[manuelkiessling]

A good example are commits journeymonitor/control@71ffae2 and journeymonitor/monitor@9cf940e. The second depends on the first, how can we verify the correctness of the complete user journey? Most elegant way would be with a testcase in JourneyMonitor, of course, however, the change is an URL within an eMail...