This gives more insight about the logs and allow setting fine-tuned
logging rules. The categories are set to only output Info by default
so this allows us to provide more concise logging while keeping the
ability to extract more information for a specific category when
developping or debugging customer issues.
Issue #5647
The csync log level was only set up on startup, and for log files.
Fix the issue by making Logger::isNoop rely on being explicitly activated
for the log window instead of relying on the presence of a connected
signal, and move the csync log level logic in Logger.
