message: mandatory tag for startTransaction
diff: "visualTagID": {
  "$ref": "tag.json#/definitions/visualID"
  }
  - }
  + },
  + "anyOf": [
  + { "required": ["tagID"] },
  + { "required": ["visualTagID"] }
  + ]
  },
  "chargePointID": {
  "$ref": "common.json#/definitions/id"
  