Feat/zookeeper version

[jbarno]

Removed readline as it is now a default and turned the Zookeeper extension into a docker arg.

[arielallon]

I can't recall: did we do any actual testing to make sure this version of php-zookeeper is functional?
from a "compatible with php 8" perspective, i don't think we have an alternative, just trying to get a sense of whether this is "stated to work" or "proven to work".