Include django contrib in stack 505

The list for ```HIDE_IN_STACKTRACE``` is rather long now and it has to be manually edited if modules are added/removed to Django. We could potentially programmatically loop through the modules of ```django```.
You're missing `django.apps` and `django.shortcuts` here. I would also include a comment at the place where django.contrib is missing to explain that the point of this list is to include everything but django.contrib.