Add telemetry docs

[knolleary]

Part of node-red/node-red#5102

Add docs for the new telemetry feature.

[Copilot]

Pull Request Overview

This PR adds documentation for the new telemetry feature as described in Node-RED issue #5102.

• Added a new "Usage Telemetry" section in the User Guide with a link to the telemetry docs.
• Created a new telemetry documentation page outlining what data is collected, why, and how users can opt out.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
docs/user-guide/index.md	Added a new section and link for usage telemetry.
docs/telemetry/index.md	Introduced a new page with comprehensive telemetry docs.

[Steve-Mcl]

Apart from the 2 typos copilot points out it reads well.

My personal take is we dont front load the information about benefits. e.g. how enabling telemetry permits update notifications, how it will help us make decisions on the direction of Node-RED project etc. I feel that could go very early in the document under the Why section.

An additional thought that occurred to me was since we are making this front and center and opt-in to enable, we could include a little more info - in particular installed modules and versions. That would provide another dimension making the data much richer. I appreciate though that you have likely considered this and have reasons for not including it here.

[Copilot]

Pull Request Overview

This PR adds documentation for the new usage telemetry feature as part of the Node-RED project. The changes include adding an entry for Usage Telemetry in the user guide and introducing a new telemetry documentation page outlining its purpose, data collected, and configuration.

• Added a "Usage Telemetry" section in the user guide with a link to the telemetry documentation.
• Created a new telemetry documentation page detailing the feature and its configuration.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
docs/user-guide/index.md	Added a new section linking to the telemetry documentation
docs/telemetry/index.md	Introduced detailed usage telemetry documentation