feat(libp2p): expose libp2p bandwidth metrics

[Stebalien]

Related Issues

Alternative to #12401
Resolves filecoin-project/go-f3#575

Proposed Changes

Exposes bandwidth metrics via opentelemetry. We do this via an async callback to avoid allocating/reporting metrics on any hot-paths. I'm using open telemetry as we've already setup a bridge for F3 and opencensus is deprecated in favor of open telemetry (so we're going to slowly move over anyways).

Checklist

Before you mark the PR ready for review, please make sure that:

• Commits have a clear commit message.
• PR title conforms with contribution conventions
• Update CHANGELOG.md or signal that this change does not need it per contribution conventions
• New features have usage guidelines and / or documentation updates in
  • Lotus Documentation
  • Discussion Tutorials
• Tests exist for new functionality or change in behavior
• CI is green

[Stebalien]

This appears to have no perf impact, but I need to test again once the splitstore stops.

[Stebalien]

@Kubuxu what do you think about this version? We should also talk about what we want in terms of otel conventions.

[Stebalien]

Ok, there's definitely no performance impact from this version.