Added an extension point to customize logging.

[jeffreycoxdoosan]

Added a LogExtensionAttribute class that can be used to override the console log template, or modify/replace the log configuration.

I confirm that the pull-request:

• [x ] Follows the contribution guidelines
• [x ] Is based on my own work
• [x ] Is in compliance with my employer

[matkoch]

I'm sorry but this is not a direction I intent to go.

[jeffreycoxdoosan]

Would you accept a pull request to just shut it off the double timestamps for Jenkins then? The reason I didn't propose that is because timestamps there configurable on the Jenkins side, but maybe most people have it turned on?