slapos_accounting: aggregate ledger from order builder

master/bt5/slapos_accounting/PathTemplateItem/portal_orders/slapos_aggregated_delivery_builder/category_movement_group_on_delivery.xml

@@ -44,6 +44,7 @@
                 <string>source_section</string>
                 <string>specialise</string>
                 <string>causality</string>
+                <string>ledger</string>
               </tuple>
             </value>
         </item>