Updates the Postfix configuration to correctly handle virtual domains when Dovecot LMTP is enabled, moving away from local system delivery settings.
- Removes `postfix_mail_domain` from `postfix_mydestination` to prevent conflicts with virtual domain handling.
- Updates `main.cf` to set `virtual_transport`, `virtual_mailbox_domains`, and `virtual_mailbox_maps` instead of `mailbox_transport`.
- Adds a new template `virtual_mailbox_maps.j2` to authorize specific users defined in `dovecot_users`.
- Adds tasks to generate the virtual mailbox map file and run `postmap` upon changes.
Introduces functionality to install and configure Dovecot alongside Postfix to provide IMAP/POP3 services.
Changes include:
- Added tasks to install Dovecot packages (core, imapd, pop3d, lmtpd).
- Added templates for main configuration and conf.d files (auth, master, ssl, mail).
- Defined default variables for protocols, SSL settings, and Maildir location.
- Enabled Postfix SASL and LMTP integration options.
- Added a handler to restart the Dovecot service.
- Updated README.md with the new configuration variables and usage instructions.
