Allow JobSchedulerLog4JAppender to only log for SOS classes

Current Situation

• JobScheduler (Master and Agent) come with log4j adapter JobSchedulerLog4JAppender
• The distributed log4j.properties file uses this adapter for all log4j-based logging
• The purpose of the adapter is to enable JITL jobs to use log4j and have the output written to spooler_log and to whatever else is configured in log4j
• Problem: The JobScheduler Universal Agent uses log4j (or logback) as well for it's own logging
  • In certain combinations of configured and used log level, the Agent's own logging will log something for remote api calls (of the job)
  • such a remote api call could be a call to spooler_log.log(...)
  • As there is only one log4j root logger in the jvm and this logger is configured to use JobSchedulerLog4JAppender, the appender will call spooler_log.log for everything that is logged by
    • jobs
    • 3rd party classes
    • the agent itself
  • so, a log4j log call (from a job) creates a spooler_log call (from the appender) creates a log4j log (from the agent) creates a spooler_log call (from the appender) ... -> endless recursion

Desired Behaviour

• JobScheduler (Master and Agent) come with log4j adapter JobSchedulerLog4JAppender
• The distributed log4j.properties file uses this adapter for the log4j-based logging of the JITL jobs
• The distributed log4j.properties file does not use this adapter for non-sos classes or the agent