feat(transport): add valkey and valkeys

[Zerotask]

This PR adds the alternative transport schemes valkey and valkeys, which is also the recommendation from django-valkey.

Fixes #2245

I didn't update the documentation because I first want to get feedback.
There could be a new page for Valkey or just an addition for the Redis transport here:
https://docs.celeryq.dev/projects/kombu/en/stable/reference/kombu.transport.redis.html

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Valkey is an open source drop-in replacement for Redis:

This project was forked from the open source Redis project right before the transition to their new source available licenses.
(https://github.com/valkey-io/valkey)

https://django-valkey.readthedocs.io/en/latest/configure/advanced_configurations.html

[Nusnus]

See celery/celery#9300

[Zerotask]

See celery/celery#9300

Thank you for referencing that. So this is a blocker and it probably needs a new Valkey transport implementation in kombu?

We recently switched from Redis to Valkey and didn't experience any issues with celery. It works as before.

[Nusnus]

See celery/celery#9300

Thank you for referencing that. So this is a blocker and it probably needs a new Valkey transport implementation in kombu?

We recently switched from Redis to Valkey and didn't experience any issues with celery. It works as before.

I don't recall all of the details, but the other issue explains where we are right now.