Change Machines to be immobilisation items, and adapt test to use computers
as an immobilised items.
Add an interface, but don't describe to much the current API which ideally
should be replaced by expandable item API.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@44438 20353a03-c40f-0410-a6d1-a30d3c3de9de