Replace code example in cluster-tutorial

[zuiderkwast]

There are code examples using antirez' redis-rb-cluster which doesn't even contain a LICENSE file, so technically it's not open source.

Replace these example with code using any of the official Valkey clients. (Python, Javascript, etc. doesn't matter as long as it can be reasonably understood by most readers.)

[avifenesh]

Will take it, in the next 1-2 weeks (unless someone closing it before)
Going to use Glide nodejs.
If will be strongly preferred can do in Glide python.
@zuiderkwast
If, on the way, there's other code pieces needed to be replaced pls let me know, I'll do all in once.

[zuiderkwast]

Go for it! I don't know about other code examples but there might be. Try a git grep. :)