feat: Run all Django services with ddtrace (Datadog APM) when enabled

[timmc-edx]

This expands the changes in edxapp to other Django services.

Also enables Datadog APM in sandboxes when Datadog is enabled overall.

See edx/edx-arch-experiments#573

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Configuration Pull Request

Make sure that the following steps are done before merging:

• Have a Site Reliability Engineer review the PR if you don't own all of the services impacted.
• If you are adding any new default values that need to be overridden when this change goes live, update internal repos and add an entry to the top of the CHANGELOG.
• Performed the appropriate testing.
• Think about how this change will affect Open edX operators and update the wiki page for the next Open edX release if needed