Adds a one-click service template for self-hosted email using Docker Mailserver.

/claim #8266

What this adds

A new template at templates/compose/docker-mailserver.yaml that deploys a production-ready mail server with:

• Postfix for SMTP (ports 25, 465, 587)
• Dovecot for IMAP (port 993)
• Rspamd for spam filtering
• Fail2ban for brute-force protection

Persistent volumes for mail data, server state, logs, and configuration.

Notes

• Users will need to update hostname and SSL paths to match their domain
• DNS records (MX, SPF, DKIM, DMARC) need to be configured separately
• ClamAV is disabled by default to reduce memory usage but can be enabled via env var

Based on the official docker-mailserver project which is actively maintained and widely used.

Fixes #8266