Reduce log during mvn tests

[relu91]

Is your feature request related to a problem? Please describe.
Right now the log is so verbose that it is almost unuseful. Its length exceeds the maximum line count in IntelliJ and TravisCI, which makes hard to pinpoint java exceptions or errors.

Describe the solution you'd like
Move most of the DEBUG messages to INFO level and use DEBUG level as default during maven build process

Describe alternatives you've considered
Another alternative is to change the debug level of maven build process ERROR.

Additional context
Issue #7 may be related to this feature request as we already removed some logging verbosity in the past.