Implement metrics API with otel

[lmolkova]

Depends on #25603 (context is there)

We want to expose metrics (for AMQP libraries as a start) on connections, events received, sent, state management) to help customers detect and alert on issues (e.g. when the number of events received on the certain partition becomes 0 it's likely to indicate an error and can help us find the exact timestamp when the issue happened).
It can give customers signals to investigate some configuration and transient network issues and give us more context with potential SDK issues.

Implementation should be otel-compatible and we'd need AzMon blessing on it.