Support opentelemetry-rust provider #60
Description
I'm not familiar with but it seems there is opentelemetry-rust crate that support OpenTelemetry and I'd like to support it so that user who don't use metrics but opentelemetry-rust can use this crate to get Promehteus style process metrics.
Maybe we should split the crate into core, metrics, and opentelemetry then enable by feature flags?