feat(cmd): add trace option to the flux cli

[jsternberg]

Done checklist

• docs/SPEC.md updated
• Test cases written

[nathanielc]

How do you use this? Looks like you need your local env to be configured to point to a jaeger install? Is the intent that it would be an existing production install? Or one inside the isolation testing env?

Does adding a trace client side associate the trace with the server side trace/spans?

[jsternberg]

It's mostly meant to be used with a local jaeger. You run the jaeger docker image and then just use --trace and it will upload it to your local one on localhost. Since this is the CLI, there are no server side trace/spans. It's just taking the existing opentracing infrastructure and allowing it to be used from the CLI.

It was originally removed when we removed the opentracing components. Then @wolffcm added better designed ones in and this became useful again.

[wolffcm]

Can we include quick instructions (or a link) somewhere on how to set up a local Jaeger? I can see this being useful.

[onelson]

https://www.jaegertracing.io/docs/1.33/getting-started/#all-in-one