Set in REQUEST the current ERP5 form & field id in a similar way as 'cell' request argument.This allows scipts used for listbox rendering be aware of current ERP5 form being rendered and access form itself. Add test for this.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@38382 20353a03-c40f-0410-a6d1-a30d3c3de9de