Add Silk middleware and related settings for performance monitoring

- Introduced SILK_ENABLED setting to toggle Silk middleware.
- Updated ALLOWED_HOSTS to include "testserver" when not in DEBUG mode.
- Modified urlpatterns to conditionally include Silk URLs.
- Added django-silk dependency to pyproject.toml.
- Enhanced feed queries to optimize performance and reduce N+1 issues.
- Updated tests to verify query limits for various feeds.

pyproject.toml

@@ -16,6 +16,7 @@ dependencies = [
     "tqdm",
     "colorama",
     "gunicorn",
+    "django-silk>=5.4.3",
 ]
 
 [dependency-groups]