🔇(helm) silence some Django system checks

Django logs some security warnings we can ignored when deploying over K8s.
Inspired by fun project, I added the Django setting SILENCED_SYSTEM_CHECKS,
and silenced the two that were logging a lot of warning.

src/backend/people/settings.py

@@ -71,6 +71,7 @@ class Base(Configuration):
     # Security
     ALLOWED_HOSTS = values.ListValue([])
     SECRET_KEY = values.Value(None)
+    SILENCED_SYSTEM_CHECKS = values.ListValue([])
 
     # Application definition
     ROOT_URLCONF = "people.urls"