[WFCORE-38] Add console option to target of console-handler

Adds an option to use the ```System.console()``` for the console-handler. Kept default of ```System.out```.
Ah, got it. Maybe adding this attribute value isn't worth it then if it means rejecting expressions. It probably doesn't add all that much as I assume stderr and stdout will be used more often. I guess too though an expression may not be used for this value often so maybe it doesn't matter...