Initial import of OTEL code supporting tracing. Metrics soon to come.
Implements APIs for https://jsr.io/@deno/otel so that code using
OpenTelemetry.js just works tm.
There is still a lot of work to do with configuration and adding
built-in tracing to core APIs, which will come in followup PRs.
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Co-authored-by: Luca Casonato <hello@lcas.dev>
