Improve Performance of "running" Order and Task Log Downloads

Current Situation

• Logs of order or tasks which are not finished (running, suspended, setback, blacklisted, waiting for resource) are not yet stored in the database.
• The JobScheduler is asked for the logs where the response contains the log in an xml element of the answer
• The whole response is loading in a DOM to extract the log which results in an OutOfMemoryError if the order or task log is too big as the whole log is stored in memory of the web service before being delivered to the client.
• It depends on the Java option -Xmx, which specifies the maximum size of the memory allocation pool.
• JOC's Jetty is started with -Xmx512m per default which causes an OutOfMemoryError being raised for logs larger than about 100MB.

Desired Behavior

• An OutOfMemoryError should not be raised for at least Order and Task logs <= 1GB.

Maintainer Notes

• At some point you reach other limits e.g. the web server of the JobScheduler doesn't respond to the JOC Cockpit web service because of a SocketTimeoutException if the log is larger than 1GB.