removed logging jars provided by HCP runtime from web archive

- debug logging did not work reliably, some categories worked and
  some did not work
- Jenkins manages JDK log level configuration which is plugged 
  in series to HCP log level configuration
- Jenkins contains slf4j-jdk14 adapter that redirects slf4j logging
  to JDK logging which is redirected again to HCP logging
- after removing logging jars from cloud-jenkins war at least slf4j
  logging in our own code shows up according to log level config
  in cloud cockpit