erp5_trade: enable template creation for purchase order

bt5/erp5_trade/PortalTypeAllowedContentTypeTemplateItem/allowed_content_types.xml

@@ -82,6 +82,7 @@
   <item>Variation Divergence Tester</item>
  </portal_type>
  <portal_type id="Preference">
+  <item>Purchase Order</item>
   <item>Sale Order</item>
  </portal_type>
  <portal_type id="Property Sheet">

bt5/erp5_trade/bt/template_portal_type_allowed_content_type_list

@@ -42,6 +42,7 @@ Order Root Simulation Rule | Net Converted Quantity Divergence Tester
 Order Root Simulation Rule | Specialise Divergence Tester
 Order Root Simulation Rule | String Divergence Tester
 Order Root Simulation Rule | Variation Divergence Tester
+Preference | Purchase Order
 Preference | Sale Order
 Property Sheet | Trade Model Line Cell Consistency Constraint
 Purchase Order Line | Purchase Order Cell