add missing bigquery params to prod params

Author: sgsmob

ansible/templates/google_symptoms-params-prod.json.j2

@@ -5,6 +5,8 @@
   },
   "indicator": {
     "export_start_date": "2020-02-20",
+    "num_export_days": 14,
+    "path_to_bigquery_credentials": "credentials.json",
     "static_file_dir": "./static"
   }
 }