Add OTEL metrics to py-hamt

[Faolain]

Motivation
py-hamt should easily send data into standard OTEL instrumentation if enabled. Most tooling/functions already support it as you can see here https://opentelemetry-python-contrib.readthedocs.io/en/latest/instrumentation/celery/celery.html and this is precisely what we have done elsewhere for other tooling which wasn't autoinstrumented/doesn't have existing OTEL plugins. Ideally with this we will be able to easily see the flow of data and see logs/spans/metrics when py-hamt is called from any applications which use it, and when we eventually integrate #82 we will see their OTEL traces/logging/metrics by default since they have them too, so all we need to do is instrument our layer.

Acceptance Criteria

• Implement conditional OTEL for logging, traces, and metrics

Addendum

• You can see how go-libp2p has already implemented OTEL (by default) here https://blog.libp2p.io/2023-08-15-metrics-in-go-libp2p/
• the javascript implementation here https://www.npmjs.com/package/@libp2p/opentelemetry-metrics