Feature Request: Consider exposing /metrics Prometheus endpoint directly

[fabriziosestito]

Is your feature request related to a problem?

We could expose a /metrics endpoint to publish metrics in Prometheus data model format, without forcing the user to install the OpenTelemetry stack.
ATM, we expose metrics via an OpenTelemtry (otlp) exporter using GRPC.

Solution you'd like

Check if this could be done by using the OpenTelemetry rust library directly,
this example here seems fitting: https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-prometheus/examples/hyper.rs
The example could be adapted to the warp web server.

Alternatives you've considered

No response

Anything else?

No response