temp: add dd trace to celery

[connorhaugh]

Description

this PR adds the ability for DD to gather traces in celery tasks, something NR does automatically. I know this is DD specific code, but a long-term solution will be coming soon.

Supporting information

https://github.com/edx/edx-arch-experiments/issues/584

Testing instructions

1. follow https://2u-internal.atlassian.net/wiki/spaces/~840928901/pages/813793298/OpenTelemetry+New+Relic+and+Datadog for devstack setup for DD, but set up the DD agent on CMS as usual
2. Follow https://2u-internal.atlassian.net/wiki/spaces/ENGAGE/pages/395673715/How+to+configure+Celery+worker+on+LMS+CMS+Devstack to set up celery workers on cms
3. Export a course
4. View the export on DD

Deadline

This will be merged ASAP and reverted no later than 4/22. A revert PR will be linked in this PR soon.