Allow setting Helix HostName for Controllers and Brokers too

Right now based on code reading, for Controllers and Brokers we are not able to update Helix Hostnames by config file.

For our cloud environment and security concern, we replace hosts very frequently, even Controllers and Brokers got replaced quickly;
In order to re-use the same Controller-Id and Broker-Id, we need to find a way to update the helix: hostname property.

P.S. This Request is created for my PR https://github.com/apache/incubator-pinot/pull/7064

Start with the linked pull request, which contains the implementation context for updating Helix hostnames through configuration. Review how Controller and Broker host properties are currently read, then verify that both components can reuse their IDs after host replacement; the issue does not name specific files or tests.

Written by the indexing model from the issue text.