COMP: Change "CLIExtensionTemplate" layout to support addition of modules.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@21745 3bd1e089-480b-0410-8dfb-8563597acbee
COMP: Change "LoadableExtensionTemplate" layout to support addition of modules.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@21746 3bd1e089-480b-0410-8dfb-8563597acbee