feat(docs): expand README to provide comprehensive IRC infrastructure overview

This commit significantly enhances the README file by restructuring and expanding its content to offer a complete overview of the IRC infrastructure setup. Key updates include:

- Introduction of core components such as UnrealIRCd, Atheme Services, and SSL/TLS management.
- Detailed sections on services integration, configuration, and automated setup processes.
- Inclusion of environment variable management with clear distinctions between public and private configurations.
- Comprehensive descriptions of security features, network architecture, and management commands.
- Added troubleshooting guidance and best practices for maintaining the IRC server.

These changes aim to improve clarity, usability, and accessibility for users setting up and managing the IRC infrastructure.

Author: kzndotsh