Add a new postConfigure flag to resolve submitted hostnames to correct reverse dns names

With the new postConfigure option -x (MCOL-1607) to not resolve hostnames to IP addresses the replication of multi node UM setups fails, if hostnames are entered whose IP address doesn't resolve into the entered hostname via reverse dns lookup.

In this case the replication connection from the secondary um to the primary fails, as the secondary's um's wrong hostname is stated in mysql.user.

This ticket should solve the issue by introducing an optional flag to -x that translates the entered hostname in postConfigure into its reverse dns lookup hostname.