Feedback on /integrate/node-red/mqtt-tutorial.md: Refer to Node-BLUE headless recipe

### Documentation feedback

- Page title: Load MQTT messages into CrateDB using Node-RED
- Page URL: https://cratedb.com/docs/guide/integrate/node-red/mqtt-tutorial.html
- Source: https://github.com/crate/cratedb-guide/blob/main/docs/integrate/node-red/mqtt-tutorial.md

---

> Launch a flow which defines a pipeline to converge data from [MQTT](https://en.wikipedia.org/wiki/MQTT) to [CrateDB](https://cratedb.com/).

```shell
# Launch Node-BLUE/Node-RED.
node-blue launch --flow=examples/flows/mqtt-to-cratedb.yaml
```
-- https://github.com/daq-tools/node-blue/blob/main/examples/flows/mqtt-to-cratedb.yaml