Queryset annotation refactor (#3117)

* Refactor out 'ordering' serializer annotation field

* Refactor BomItem serializer annotations

* Factor out MPTT OuterRef query

* Add 'available_stock' annotation to SalesOrderLineItem serializer

- Allows for better rendering of stock availability in sales order table

* Improve 'available quantity' rendering of salesorderlineitem table

* Bump API version

* Add docstring

InvenTree/order/api.py

@@ -788,6 +788,8 @@ class SalesOrderLineItemList(generics.ListCreateAPIView):
             'order__stock_items',
         )
 
+        queryset = serializers.SalesOrderLineItemSerializer.annotate_queryset(queryset)
+
         return queryset
 
     filter_backends = [
@@ -835,6 +837,14 @@ class SalesOrderLineItemDetail(generics.RetrieveUpdateDestroyAPIView):
     queryset = models.SalesOrderLineItem.objects.all()
     serializer_class = serializers.SalesOrderLineItemSerializer
 
+    def get_queryset(self, *args, **kwargs):
+        """Return annotated queryset for this endpoint"""
+        queryset = super().get_queryset(*args, **kwargs)
+
+        queryset = serializers.SalesOrderLineItemSerializer.annotate_queryset(queryset)
+
+        return queryset
+
 
 class SalesOrderContextMixin:
     """Mixin to add sales order object as serializer context variable."""