Provide module for 3rd party tool Celery

[data-matt]

Is your feature request related to a problem? Please describe.
Hi, one of our customers is asking if we have plans to integrate with Celery the Distributed Task Queue.

Currently celery provides an route to use Cockroachdb as a results backend, it is via SQLAlchemy
https://docs.celeryproject.org/en/3.1/getting-started/brokers/sqlalchemy.html

For more details, please see:
https://github.com/celery/celery

Describe the solution you'd like
Create a module for cockroachdb

Describe alternatives you've considered
Use SQLalchemy as a backend.

gz#10569

Jira issue: CRDB-11412

[kernfeld-cockroach]

For the time being I suggest using the SQLAlchemy backend since CockroachDB is already compatible with SQLAlchemy.