Add SingleUUIDObjectMixin

We can use this mixin to get an object by its UUID in the URLconf.

src/backoffice/views/mixins.py

 from django.conf import settings
 from django.contrib.auth.mixins import LoginRequiredMixin, PermissionRequiredMixin
 from django.core.exceptions import PermissionDenied
-from django.http import HttpRequest, HttpResponse
+from django.http import Http404, HttpRequest, HttpResponse
 from django.shortcuts import redirect
 from django.urls import reverse, reverse_lazy
 from django.utils.translation import gettext_lazy as _
+from django.views.generic.detail import SingleObjectMixin
 from rules.contrib.views import PermissionRequiredMixin as RulesPermissionRequiredMixin
 
 from core.models.assemblies import Assembly
@@ -17,6 +18,7 @@ from core.models.sso import Application
 class ConferenceRequiredMixinBase:
     login_url = reverse_lazy('backoffice:login')
     require_conference = False
+    _conference: Conference | None = None
     _conferencemember: ConferenceMember | None = None
 
     def __init__(self, *args, **kwargs):
@@ -429,3 +431,32 @@ class PasswordMixin:
         )
 
         return context
+
+
+class SingleUUIDObjectMixin(SingleObjectMixin):
+    uuid_url_kwarg = 'uuid'
+
+    def get_object(self, queryset=None):
+        """
+        Return the object the view is displaying.
+
+        Require `self.queryset` and a `uuid` argument in the URLconf.
+        Subclasses can override this to return any object.
+        """
+        # Use a custom queryset if provided; this is required for subclasses
+        # like DateDetailView
+        if queryset is None:
+            queryset = self.get_queryset()
+
+        uuid = self.kwargs.get(self.uuid_url_kwarg)
+        if uuid is not None:
+            queryset = queryset.filter(uuid=uuid)
+        else:
+            raise AttributeError(f'Generic detail view {self.__class__.__name__} must be called with an object uuid in the URLconf.')
+
+        try:
+            # Get the single item from the filtered queryset
+            obj = queryset.get()
+        except queryset.model.DoesNotExist as exc:
+            raise Http404(_('No %(verbose_name)s found matching the query') % {'verbose_name': queryset.model._meta.verbose_name}) from exc
+        return obj