Refactor the documentation to accurately describe the role as a complete internal mail server stack including Postfix and Dovecot.
Changes include:
- Expanded the description to explicitly list components and internal use cases.
- Added a section clarifying excluded features (antispam/antivirus).
- Reorganized role variables into General and Postfix configuration tables.
- Cleaned up Markdown formatting and removed excessive bold styling.
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.
