Log level change requires full restart

[charith-elastic]

Follow-up from #3570

Once the log level is set, it cannot be changed again without completely stopping the operator and restarting it. This is due to the use of the global Log variable in the controller-runtime log package. Even though it can be replaced with a new logger, existing loggers created from the previous logger will not be updated -- which makes it difficult to effect a global log level change in code.

[pebrc]

Known issue we won't fix.