This role will install postfix and configure it for either 'Local only' or 'Satellite system' type. The others aren't supported by this role, at this time.
ansible_role_postfix_type: one of 'Satellite system' or 'Local only'
ansible_role_postfix_mailname: defaults to ansible_fqdn
If ansible_role_postfix_type is 'Satellite system', the following variable is required:
ansible_role_postfix_relayhost: <fqdn or IP of your mail relay host>