Document how to integrate Node-Red with InfluxDB 2 (cloud + OSS)

**Problem:**
We don't provide any official documentation on how to integrate Node-Red with InfluxDB 2 (cloud + OSS). A google search for "node red influxdb" turns up a couple of pages that describe integration with InfluxDB 1.x:

https://flows.nodered.org/node/node-red-contrib-influxdb
https://flows.nodered.org/flow/1d06cc6dbb57544f2d8b

... but unfortunately, these leave out important details, such as the correct port number (8086 versus 9999).

**Request**:
Please provide documentation on how to:

1. Send data from Node-Red into InfluxDB 2, both OSS and Cloud
2. Get data out of InfluxDB 2, both OSS and Cloud, and into Node-Red
3. Let me know once done, so I can ask our web team to produce a Node-Red landing page to help with SEO and guide developers to how we can help them.

**Background**:
If you're not already familiar with it, Node-Red is a popular open source low-code integration platform. It is built using Node.js and npm, and is popular with IoT developers:

https://github.com/node-red/node-red
https://nodered.org/

Node-Red has over 2500 libraries to get, process, and send data. So, it's essentially Telegraf on steroids. Supporting it fully would greatly help our ability to fully support IoT developers.

Note that this Node-Red library can both send and retrieve data from InfluxDB:

https://flows.nodered.org/node/node-red-contrib-influxdb

Also note that some developers like to use MQTT to get data in and out of InfluxDB, which is another path we may want to consider documenting:

https://flows.nodered.org/flow/83617792aa2c2f50d15ed71f840d9905

https://flows.nodered.org/flow/dc9754a796fac49c918ab5a94f0af58a

Start by reviewing the node-red-contrib-influxdb library and the linked Node-Red flows, focusing on how they send data to and retrieve data from InfluxDB 2. Document both OSS and Cloud integrations, including the correct connection details and ports; consider whether the MQTT flows belong in the guide. Done means users can follow documented steps for both directions and both deployment types.

Written by the indexing model from the issue text.