Introduce detail and edit URLs as properties in AK model

This way, the frontend views will be used when AKSubmission is installed and active, or otherwise the link to the built-in AK edit form in backend
This reduces the coupling between AKSubmission and other apps that previously needed that app
Use that new property in all places where previously an URL to the submission view was used (for consistency and to allow changes in one place in AKSubmission, too)
This implements #166

AKSubmission/views.py

@@ -199,7 +199,7 @@ class AKAndAKWishSubmissionView(EventSlugMixin, EventInactiveRedirectMixin, Crea
 
     def get_success_url(self):
         messages.add_message(self.request, messages.SUCCESS, _("AK successfully created"))
-        return reverse_lazy('submit:ak_detail', kwargs={'event_slug': self.kwargs['event_slug'], 'pk': self.object.pk})
+        return self.object.detail_url
 
     def form_valid(self, form):
         if not form.cleaned_data["event"].active:
@@ -249,7 +249,7 @@ class AKEditView(EventSlugMixin, EventInactiveRedirectMixin, UpdateView):
 
     def get_success_url(self):
         messages.add_message(self.request, messages.SUCCESS, _("AK successfully updated"))
-        return reverse_lazy('submit:ak_detail', kwargs={'event_slug': self.kwargs['event_slug'], 'pk': self.object.pk})
+        return self.object.detail_url
 
     def form_valid(self, form):
         if not form.cleaned_data["event"].active:
@@ -287,7 +287,7 @@ class AKOwnerCreateView(EventSlugMixin, EventInactiveRedirectMixin, CreateView):
             ak.owners.add(self.object)
             messages.add_message(self.request, messages.SUCCESS,
                                  _("Added '{owner}' as new owner of '{ak.name}'").format(owner=self.object, ak=ak))
-            return reverse_lazy('submit:ak_detail', kwargs={'event_slug': self.kwargs['event_slug'], 'pk': ak.pk})
+            return ak.detail_url
         return reverse_lazy('submit:submit_ak',
                             kwargs={'event_slug': self.kwargs['event_slug'], 'owner_slug': self.object.slug})
 
@@ -375,8 +375,7 @@ class AKSlotAddView(EventSlugMixin, EventInactiveRedirectMixin, CreateView):
 
     def get_success_url(self):
         messages.add_message(self.request, messages.SUCCESS, _("AK Slot successfully added"))
-        return reverse_lazy('submit:ak_detail',
-                            kwargs={'event_slug': self.kwargs['event_slug'], 'pk': self.object.ak.pk})
+        return self.object.ak.detail_url
 
 
 class AKSlotEditView(EventSlugMixin, EventInactiveRedirectMixin, UpdateView):
@@ -389,7 +388,7 @@ class AKSlotEditView(EventSlugMixin, EventInactiveRedirectMixin, UpdateView):
         if akslot.start is not None:
             messages.add_message(self.request, messages.WARNING,
                                  _("You cannot edit a slot that has already been scheduled"))
-            return redirect('submit:ak_detail', event_slug=self.kwargs['event_slug'], pk=akslot.ak.pk)
+            return HttpResponseRedirect(akslot.ak.detail_url)
         return super().get(request, *args, **kwargs)
 
     def get_context_data(self, *, object_list=None, **kwargs):
@@ -399,8 +398,7 @@ class AKSlotEditView(EventSlugMixin, EventInactiveRedirectMixin, UpdateView):
 
     def get_success_url(self):
         messages.add_message(self.request, messages.SUCCESS, _("AK Slot successfully updated"))
-        return reverse_lazy('submit:ak_detail',
-                            kwargs={'event_slug': self.kwargs['event_slug'], 'pk': self.object.ak.pk})
+        return self.object.ak.detail_url
 
 
 class AKSlotDeleteView(EventSlugMixin, EventInactiveRedirectMixin, DeleteView):
@@ -412,7 +410,7 @@ class AKSlotDeleteView(EventSlugMixin, EventInactiveRedirectMixin, DeleteView):
         if akslot.start is not None:
             messages.add_message(self.request, messages.WARNING,
                                  _("You cannot delete a slot that has already been scheduled"))
-            return redirect('submit:ak_detail', event_slug=self.kwargs['event_slug'], pk=akslot.ak.pk)
+            return HttpResponseRedirect(akslot.ak.detail_url)
         return super().get(request, *args, **kwargs)
 
     def get_context_data(self, *, object_list=None, **kwargs):
@@ -422,8 +420,7 @@ class AKSlotDeleteView(EventSlugMixin, EventInactiveRedirectMixin, DeleteView):
 
     def get_success_url(self):
         messages.add_message(self.request, messages.SUCCESS, _("AK Slot successfully deleted"))
-        return reverse_lazy('submit:ak_detail',
-                            kwargs={'event_slug': self.kwargs['event_slug'], 'pk': self.object.ak.pk})
+        return self.object.ak.detail_url
 
 
 class AKAddOrgaMessageView(EventSlugMixin, CreateView):
@@ -444,5 +441,4 @@ class AKAddOrgaMessageView(EventSlugMixin, CreateView):
 
     def get_success_url(self):
         messages.add_message(self.request, messages.SUCCESS, _("Message to organizers successfully saved"))
-        return reverse_lazy('submit:ak_detail',
-                            kwargs={'event_slug': self.kwargs['event_slug'], 'pk': self.object.ak.pk})
+        return self.object.ak.detail_url