OpenTelemetry support

[sagikazarmark]

I added go-kit to the OpenTelemetry contrib repo: https://github.com/open-telemetry/opentelemetry-go-contrib/tree/main/instrumentation/github.com/go-kit/kit/otelkit

It's based on the OpenCensus implementation.

[peterbourgon]

How shall we manage this on our side? A link somewhere?

[sagikazarmark]

I guess we can add a link somewhere, yes.

[sagikazarmark]

It's now released: https://github.com/open-telemetry/opentelemetry-go-contrib/releases/tag/v0.19.0