OZG-6239 Remove unused files

...cloud/xta/test/app/config/ClientConnectionProperties.java

...ava/de/ozgcloud/xta/test/app/config/ClientProperties.java

.../ozgcloud/xta/test/app/config/MapStructConfiguration.java

.../ozgcloud/xta/test/app/config/XtaConfigQualifierType.java

.../ozgcloud/xta/test/app/config/XtaTesterConfiguration.java

...cloud/xta/test/app/exception/CancelScenarioExecution.java

...gcloud/xta/test/app/exception/ConfigurationException.java

...e/ozgcloud/xta/test/app/exception/XtaTesterException.java

src/main/resources/application_second_app.yml

src/main/resources/defaultEncodedFile.txt

...est/java/de/ozgcloud/xta/test/app/TestingApplication.java