This reference is generated with help of short title of portal_type as prefix.
If short title is not filled, all capital letters of portal_type string will be used.

*The computation of this reference will probably be delegated to a specific tool like portal_ids.*

Add read-only field on Event_view to display the reference
add additional column in listbox of Event Module

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@38274 20353a03-c40f-0410-a6d1-a30d3c3de9de