Currently horizon-operator queries the pods deployed by infra-operator to generate serverList, but this is quite redundant and not very robust.

• Querying individual pods is considered to be costly
• This duplicate queries in case a single Memcached instance is used by multiple services
• The current logic does not detect IP version, and additional query is needed to obtain that infomcation

This sub-task is created to generalize the current implementation and move it to infra-operator, so that we can reuse the implementation in all operators later.