Part responsible owner (#5774)

* Add "responsible_owner" field to part model

- Will replace "responsible" field

* Data migration

- Adds 'responsible_owner' value for parts which have 'responsible' set
- Selects correct content type
- Performs reverse migratoin

* Update part serializer

- Point to the new field
- Rename to preserve compatibility
- OPTIONS metadata will take care of the rest

* Remove old 'responsible' field

* Bump API version

* Fix typo

* Fix serializer field

InvenTree/part/serializers.py

@@ -26,6 +26,7 @@ import part.filters
 import part.stocktake
 import part.tasks
 import stock.models
+import users.models
 from InvenTree.status_codes import BuildStatusGroups
 from InvenTree.tasks import offload_task
 
@@ -695,6 +696,12 @@ class PartSerializer(InvenTree.serializers.RemoteImageMixin, InvenTree.serialize
         read_only=True,
     )
 
+    responsible = serializers.PrimaryKeyRelatedField(
+        queryset=users.models.Owner.objects.all(),
+        required=False, allow_null=True,
+        source='responsible_owner',
+    )
+
     # Annotated fields
     allocated_to_build_orders = serializers.FloatField(read_only=True)
     allocated_to_sales_orders = serializers.FloatField(read_only=True)