Allow for use of hostnames in advertised_kafka_api and other locations

[patrickangeles]

Presently, the ansible scripts work off a set of IP addresses to configure broker nodes. These IP addresses are used to identify listener bindings but also to come up with the list of seed brokers and advertised addresses. We should allow for the passing of hostnames to be used for advertised addresses and other things.

[freef4ll]

It is also useful in Terraform to refer to the nodes via host name and export the availability zone and setting that in the config

templates/hosts_ini.tpl:

[redpanda]
%{ for i, ip in redpanda_public_ips ~}
${redpanda_public_dns[i]} ansible_host=${ ip } ansible_user=${ ssh_user } ansible_become=True private_ip=${redpanda_private_ips[i]} id=${i} zone=${redpanda_availability_zone[i]}
%{ endfor ~}

ansible/playbooks/start-redpanda.yml:

sudo rpk redpanda config set redpanda.rack {{ hostvars[inventory_hostname].zone }}