Backport "PHOENIX-5215 Migrate from HTrace to OpenTelemetry tracing" #894

Phoenix still relies on HTrace which has 53 or so vulnerabilities.

Unfortunately the upstream PR hasn't moved since March (and mine since July) so I think we shouldn't wait and just backport it ourselves.

So, take this PR apache/phoenix#2586 create a patch out of it and backport it to our Phoenix.

I hope it applies cleanly to our Phoenix version. If this takes longer than a day let me know. It should not.