[Enhancement]: Docs/example for redis cluster

[hughesjj]

Proposal

I'm a maintainer of opentelemetry-collector-contrib/receiver/redis, and have attempted to implement testing a redis cluster. This is important as some metrics only appear (ctrl+f If the instance is a replica) when a redis is configured as a cluster.

While we have good examples for creating a single redis container, it would be nice to do so as well for clusters.
It seems like I'm not alone in this desire, as someone had previously tried the same

I'll note that this line of desire would also apply to kafka, and pretty much every open source distributed service.

[JY8752]

@hughesjj
I also want to write a test for redis cluster using testcontainers but it is failing. Please let me know if you make any progress!!