Clarify Celery integration init docs

[szokeasaurusrex]

Core or SDK?

Platform/SDK

Which part? Which one?

Python SDK (Celery integration)

Description

The docs for setting up the Python SDK's Celery integration should be rewritten to more clearly inform users that Sentry needs to be initialized from either within the celeryd_init or worker_init signals in order for Sentry to work properly when Celery is used without Django. We currently document this in the Standalone Setup section.

Suggested Solution

My proposal would be to remove the code sample that we currently provide in the Configure section.

Instead, we should instruct users to initialize Celery per the Django integration docs when they are using Celery with Django.

Then, we would provide the Standalone Setup sample for users who are using Celery alone as a queue without Django. We should remove the term "Celery standalone" from the page, since this terminology is non-standard; a Google search for "Celery standalone" yields no relevant results. Instead, we should explain that the signal-handler setup is needed when using Celery without Django.