Tweak prod3
Finally an actually working version to run overlay consistently for the z-uds samples.
BEGINRELEASENOTES
*Core
CHANGE: GetOverlayFiles module renamed to :mod:~ILCDIRAC.Core.Utilities.OverlayFiles
and added some helper functions to it; reduce code duplication in the OverlayInput interface and workflow module
ENDRELEASENOTES
Edited by Andre Sailer