Implement Tracing in stacks-devnet-api

Add tracing capabilities which implement the [otel protocol](https://opentelemetry.io/docs/specs/otel/protocol/). We can start with auto-instrumentation to generate traces and spans for all network requests, and add custom instrumentation later to generate more in-depth spans for function calls if desired.

[The OpenTelemetry Rust library can be used for this.](https://github.com/open-telemetry/opentelemetry-rust)

Start by locating the server entry point and the code that handles network requests in stacks-devnet-api, then review how the Rust service currently starts and exposes requests. Add OpenTelemetry-compatible tracing for those requests, with generated traces and spans, and verify that the instrumentation is emitted through the selected protocol.

Scritto dal modello di indicizzazione a partire dal testo della issue.