[WIP] OTEL Observability

[IshanDaga]

Feature

Using OTEL lib to instrument the server. Happy to take suggestions on things that we should track, metrics to add, and how to allow maximum configurability for the Tracer.

Tasks

• [x] Add context object to each packet
• [x] Add OTEL config options to server.Options struct
• [ ] Add spans for client events
• [ ] Add metrics tracking using OTEL Meters API
• [ ] Instrument slog handler

Pending decisions

• [ ] should we add another external dependency like https://github.com/ttys3/slogx to internally instrument slog, or should we leave that to the user to implement within their own hook implementations ?