- refactor profiles::postfix::gateway as parameterized class
- move base postfix parameters, transports, and virtuals in hiera for deep merging
- convert SMTP restrictions to arrays for better readability using join()
- add postscreen enable/disable boolean with conditional master.cf configuration
- add per-domain TLS policy maps (smtp_tls_policy_maps)
- convert alias_maps to array parameter for flexibility
- add voxpupuli-postfix module to Puppetfile
- create profiles::postfix::gateway class with config based on efa5
- add master.cf entries for postscreen, smtpd, dnsblog, and tlsproxy services
- create postfix hash files: aliases, access controls, canonical maps
- configure TLS with system PKI certificates and strong cipher suites
- add transport and virtual alias mappings for mail routing
Reviewed-on: #414
