Add `resolve-hostnames` support for Sentinel

[loliee]

This Pull request add support for the Sentinel option: resolve_hostnames.

⚠️ From documentation:

This capability is disabled by default. If you're going to enable DNS/hostnames support, please note: 1. The name resolution configuration on your Redis and Sentinel nodes must be reliable and be able to resolve addresses quickly. Unexpected delays in address resolution may have a negative impact on Sentinel. 2. You should use hostnames everywhere and avoid mixing hostnames and IP addresses. To do that, use replica-announce-ip and sentinel announce-ip for all Redis and Sentinel instances, respectively.