COMP: Update Editor extension template to use scripted module macro

Discussion: http://slicer-devel.65872.n3.nabble.com/Issues-with-Editor-effect-extension-td4029730.html

Fixes #3392

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22427 3bd1e089-480b-0410-8dfb-8563597acbee
COMP: Simplify editor extension template

This is a follow up of commit r22067 [1] where it should have been done
as described in r22063 [2].

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22428 3bd1e089-480b-0410-8dfb-8563597acbee