feat(events): add EventDeleteView for permanent event deletion

- Add EventDeleteView with DELETE /api/v1/events/<pk>/delete/
- Register delete URL in admin_api/urls.py

admin_api/urls.py

@@ -30,6 +30,7 @@ urlpatterns = [
     path('events/<int:pk>/', views.EventDetailView.as_view(), name='event-detail'),
     path('events/<int:pk>/update/', views.EventUpdateView.as_view(), name='event-update'),
     path('events/<int:pk>/moderate/', views.EventModerationView.as_view(), name='event-moderate'),
+    path('events/<int:pk>/delete/', views.EventDeleteView.as_view(), name='event-delete'),
     path('events/create/', views.EventCreateView.as_view(), name='event-create'),
     path('events/types/', views.EventTypesView.as_view(), name='event-types'),
     path('events/<int:pk>/primary-image/', views.EventPrimaryImageView.as_view(), name='event-primary-image'),