Import for OpenTelemetry traces

Just wanted to have this tracked, as it needs some further exploration on what we can do with traces in the profiler and how useful it would be.

Resources:

* https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/overview.md#trace
* https://lightstep.com/blog/opentelemetry-101-what-is-tracing/
* https://www.jaegertracing.io/

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-258)

Start with the linked OpenTelemetry specification, the Lightstep tracing overview, and the Jaeger resource to understand the proposed trace model. Explore how traces could fit into the profiler and define a useful import scope and completion criteria before implementation; the issue names no files or tests.

Written by the indexing model from the issue text.