Support encrypted passwords in GitLab KAS

Overview

gitlab_kas['redis_password'] currently needs to be set as plaintext in /etc/gitlab/gitlab.rb and will end up as plaintext in their respective configuration files until GitLab Exporter supports encrypted passwords, like GitLab Rails. Once the backend work is done, Distribution can take on the work to expose necessary settings in /etc/gitlab/gitlab.rb.

References

This issue is the follow-up of the discussion started in omnibus-gitlab#6275 (comment 1672764675)