Define manage_renameObject in ERP5Site. Note that this implementation is good enough for the unit test, but far from perfect. The future implementation must use activities very carefully to reduce the memory footprint.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@16727 20353a03-c40f-0410-a6d1-a30d3c3de9de