cmk-update-config - Logging to file

The command cmk-update-config logs errors to STDOUT.

To allow for enhanced useability, reportability and so on, a logging to file in addition to the STDOUT should be implemented. This would greatly improve the auditing and verification capabilities, helping Checkmk to align to regulatory terms and give potential to organisations to use that log files for automation purposes.

The effort required to deploy this is expected to be trivially low as file logging is already in place for other modules.