Add audit event for suspending a service

This is particularly important for broadcast services, where a rogue
service or platform admin could launch a DoS attack by suspending a
service at a critical moment when it needs to send alerts.

app/event_handlers.py

@@ -67,6 +67,17 @@ def create_broadcast_account_type_change_event(
     )
 
 
+def create_suspend_service_event(
+    service_id,
+    suspended_by_id,
+):
+    _send_event(
+        'suspend_service',
+        service_id=service_id,
+        suspended_by_id=suspended_by_id,
+    )
+
+
 def _send_event(event_type, **kwargs):
     event_data = _construct_event_data(request)
     event_data.update(kwargs)