slapos_erp5: allow Sale agent/manager to handle Assignments

master/bt5/slapos_erp5/PortalTypeRolesTemplateItem/Assignment.xml

 <type_roles>
-  <role id='Auditor'>
-   <property id='title'>Information System</property>
-   <property id='description'>XXX local role group</property>
-   <multi_property id='category'>function/is*</multi_property>
+  <role id='Assignee'>
+   <property id='title'>Sale Agent</property>
+   <multi_property id='categories'>local_role_group/function</multi_property>
+   <multi_property id='category'>function/sale/agent</multi_property>
+   <multi_property id='base_category'>function</multi_property>
+  </role>
+  <role id='Assignor'>
+   <property id='title'>Sale Manager</property>
+   <multi_property id='categories'>local_role_group/function</multi_property>
+   <multi_property id='category'>function/sale/manager</multi_property>
    <multi_property id='base_category'>function</multi_property>
   </role>
 </type_roles>
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