Properly report test results

Created by: jlHertel

We are currently running tests but not giving the output and the artifacts to jenkins for archiving. One idea is to output it using the XML format and then convert it to JUnit, like is sugested in this Thread: https://stackoverflow.com/questions/11540633/using-gtest-in-jenkins

Additional info on testing and archiving: https://jenkins.io/doc/pipeline/tour/tests-and-artifacts/