Added tests on source

src/main/java/beamline/mappers/package-info.java

.../java/beamline/models/algorithms/HookEventProcessing.java

src/main/java/beamline/sources/MQTTXesSource.java

src/test/java/beamline/tests/SourcesTest.java

src/test/java/beamline/tests/Utils.java

src/test/java/beamline/tests/UtilsTest.java