Harmonize tracing library usages

[adriansmares]

Summary

We currently trace sections using both runtime/trace and OTEL tracing. We should harmonize this towards OTEL tracing, which is a super set of runtime/trace.

Current Situation

We currently use runtime/trace in most places, except the Identity Server bunstore.

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

In order to harmonize racing towards OpenTelemetry.

Proposed Implementation

Use tracer.StartFromContext instead of trace.StartRegion, and consider adding attributes.

Contributing

• [X] I can help by doing more research.
• [X] I can help by implementing the feature after the proposal above is approved.
• [X] 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]

Nice. I'll pick this up since this was triggered from one of my PRs.