allow optional configuration of log levels

[tgjonestx]

Currently configuration of the logger can only be controlled from the command line which is hard-coded in the Dockerfile. For debugging notifiers, including custom notifiers, it would be nice if the notifier configuration supported optional parameters that allowed for the configuration of the logger (e.g. log level = debug).

If the configuration properties for logging are not specified, then the notifier should default to the current behavior.