Fix default ordering for build orders (#3626)

- Order by reference
- Show "newer" references first

InvenTree/build/api.py

@@ -100,6 +100,8 @@ class BuildList(APIDownloadMixin, ListCreateAPI):
         'reference': ['reference_int', 'reference'],
     }
 
+    ordering = '-reference'
+
     search_fields = [
         'reference',
         'title',

InvenTree/order/api.py

@@ -292,7 +292,7 @@ class PurchaseOrderList(APIDownloadMixin, ListCreateAPI):
         'status',
     ]
 
-    ordering = '-creation_date'
+    ordering = '-reference'
 
 
 class PurchaseOrderDetail(RetrieveUpdateDestroyAPI):
@@ -733,7 +733,7 @@ class SalesOrderList(APIDownloadMixin, ListCreateAPI):
         'customer_reference',
     ]
 
-    ordering = '-creation_date'
+    ordering = '-reference'
 
 
 class SalesOrderDetail(RetrieveUpdateDestroyAPI):