CORE: moved log4j to src/test/resources

- Prevent from adding log4j.xml/.properties in runtime classpath,
  by muving them to tests (it will be used in tests only).
- Shouldn't really affect any of our apps, since we use
  custom log4j config location anyway.

- Any app including perun-core can now define own log4j
  config and then must define logging for whole application
  including perun-core.

  So it should be possible now to run perun-rpc and other
  perun application in same tomcat (I didn't test it).