Resolve new sentinels ips if cloud nodes changed

[OpakAlex]

Issue: If you use kubernetes redis chart: https://hub.docker.com/r/bitnami/redis/ with sentinels support and Preemptible google cloud nodes, then you will have issue when your nodes recreated, ip address changed, and then your redis connection stop working, also sidekiqs, etc.

Solution: Provide an resolver (lambda function) which can resolve new ip address by host name for sentinels nodes, and reset @sentinels variable for choose connection.