Bump zookepper operator version to 0.2.15

[GrahamCampbell]

Bumps the version of the Zookeeper Operator to 0.2.15 and avoid a redirect hop.

[Slach]

please make following command

git add remove upstream git@github.com:Altinity/clickhouse-operator.git
git checkout 0.23.0
git pull upstream 0.23.0
git merge zookeeper-operator-version

and fix the conflicts