v3.5.0: feat: Robustness improvements to datadog_diagnostics plugin (#723)

- Add `DATADOG_DIAGNOSTICS_ENABLE` for quick disable if needed
- Limit spans with `DATADOG_DIAGNOSTICS_MAX_SPANS` (default 100)
- Fix scope of member variables
- Add unit tests

Manual testing:

- Modify `common.djangoapps.student.views.dashboard.student_dashboard` in
  edx-platform to call `import time; time.sleep(10)` at the start of the
  view.
- Start server and log
- Visit /dashboard
- While the browser is waiting, quickly make a small edit to an
  edx-platform file, causing an autoreload.
- Confirm that spans are logged.

v3.4.0: feat: Add datadog_diagnostics plugin app (#722)

See https://github.com/edx/edx-arch-experiments/issues/692

Testing setup:
https://2u-internal.atlassian.net/wiki/spaces/ENG/pages/1173618788/Running+Datadog+in+devstack

And then in lms-shell:

```
make requirements
pip install ddtrace
pip install -e /edx/src/archexp/
./wrap-datadog.sh ./server.sh
```

Expect to see this log message:
`Attached MissingSpanProccessor for Datadog diagnostics`

NOTE: This prints "Spans created = 0; spans finished = 0" in devstack when
shut down with ctrl-c, but not when restarted due to autoreload (where it
prints correct info). Something is initializing Django twice and one span
processor is getting span info while the other is printing at shutdown.
There's more to debug here, but it seems stable enough to least try
deploying it.

v3.3.2: Merge pull request #603 from edx/diana/add-translatable

feat: Add translatable-xblocks to code owners.

v3.3.1

What's Changed

• feat: add python 3.12 support by @edx-requirements-bot in #554

Full Changelog: v3.3.0...v3.3.1

v3.3.0

See changelog

v3.2.0

See changelog

v3.1.1

see changelog

v3.1.0: feat: Log addition of config watchers and make receivers unique (#487)

See changelog

v3.0.0

See changelog.

v2.2.0: feat: Add Waffle config watcher (#481)

See changelog