Restructure integration tests

We have the integration tests 'as it' and

we have the verification check integration tests.

Now we restructure those two projects into one common folder.
Use getModel/persistModel
Reduce log level when logging infrastucture cannot be setup.

Log level is now warn and not error anymore. We use reasonable defaults in
case we cannot set the MavenLogger.
Integration test for verification checks in module builds.
Started refactored test parameters + improved check test
Update license header so that it does not complain in the continuous-integration build
Fix missing license header in new file.
Introduce builder for TestParams.
Introduced constants for Maven Coordinate names