add two properties in propertySheet M0, because in the M0 form, the field Logo is separate in two fields ( Initials and sign ).
update propertySheet PsjOrganisation with two fields ( sign and acronym ).

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@22846 20353a03-c40f-0410-a6d1-a30d3c3de9de