Standalone server: use processes instead of threads

This improves the reliability and performance of the app, it means
multiple requests can be processes simultaneously whereas with a single
process, the server would stay blocked until it finished responding to
the first request.

Change-Id: I92ef93a4b30b93036c5a70735962c97229f78840

ara/manage.py

@@ -37,7 +37,8 @@ manager.add_command(
     "runserver",
     commands.Server(host=app.config['ARA_HOST'],
                     port=app.config['ARA_PORT'],
-                    threaded=True)
+                    processes=8,
+                    threaded=False)
 )