After having tried using the logging from SKARA-971 to track down a problem, I've realized a couple of things that need improving.

With this change, we no longer get stacktraces logged as those are typically logged on FINER level. We either need to change this, or store logging from FINER in logstash as well.

I also noticed that we aren't saving the name of the logger in any field in logstash. Adding this should help tracking down the source of a log message a lot quicker.