Consider switching metrics library from Prometheus to OpenTelemetry

[htdvisser]

Summary

Once the OpenTelemetry Go libraries have stable support for metrics (see https://github.com/open-telemetry/opentelemetry-go/milestones) we should consider switching from using the Prometheus library to the OpenTelemetry library.

Current Situation

We're using the Prometheus library (and a little bit of OpenCensus) for our metrics. The OpenTelemetry library looks promising, but is still work in progress.

Why do we need this? Who uses it, and when?

There's nothing wrong with Prometheus, and OpenTelemetry metrics are still work in progress, but we should keep an eye on it. I think it can be really valuable if this allows us to better correlate metrics and traces (and in the future even logs).

Proposed Implementation

No response

Contributing

• [ ] I can help by doing more research.
• [ ] I can help by implementing the feature after the proposal above is approved.
• [ ] I can help by testing the feature before it's released.

Code of Conduct

• [X] I agree to follow TTN's Community Code of Conduct.

[KrishnaIyer]

Let's revisit this when needed.