Integrate Tomcat logs to graylog

[jochen]

You can either collect the log files written by Apache Tomcat via Filebeat or NXLOG (also see http://docs.graylog.org/en/2.4/pages/collector_sidecar.html) or configure the logging subsystem of your Apache Tomcat to send logs directly to Graylog, e. g. with a GELF appender:

• https://github.com/mp911de/logstash-gelf/
• https://tomcat.apache.org/tomcat-9.0-doc/logging.html