[telemetry] Define lifecycle and stability of telemetry

[mx-psi]

On the GA Roadmap, we have

• Metrics, or a subset of them, should be marked as stable in the documentation
• [...]
• Stability expectations and lifecycle for telemetry should be documented, so that users can know what they can rely on for their dashboards and alerts

A starting point can be https://kubernetes.io/docs/concepts/cluster-administration/system-metrics/#metric-lifecycle

[lavishpal]

@mx-psi
Could you assign this issue to me and it will be helpful if you provide guidance on how to get started?

[mx-psi]

@lavishpal We can start with a document that lists out what we guarantee from a stable metric (in terms of what can change). We can initially host the document in the docs/ folder of this repository. Once we have that, we can consider next steps

[tiffany76]

During the Comms SIG meeting on August 5, we discussed where this content should live: website or repo. Since the lifecycle of the telemetry affects whether it can be used, the group felt this content belongs on the website where it can benefit end users. We are seeking additional comments as well.