add comprehensive documentation for all Ansible roles

- Add main README with infrastructure overview and usage instructions
- Document bootstrap role for server initialization and security hardening
- Document common role for shared server configuration
- Document cron role for scheduled tasks and automation
- Document docker role with detailed service descriptions and deployment patterns
- Include MMDL service documentation with setup requirements
- Add troubleshooting guides and security considerations

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

roles/common/README.md

@@ -0,0 +1,23 @@
+# Common Role
+
+## Purpose
+Provides shared configuration and security setup that applies to all servers in the infrastructure.
+
+## What It Does
+
+### System Packages
+- Installs `aptitude` for better package management and dependency resolution
+- Updates package cache to ensure latest package information
+
+### Security Configuration
+- Enables UFW (Uncomplicated Firewall) with default deny policy
+- Provides baseline firewall protection for all managed servers
+
+## Usage
+This role is automatically applied to all servers in the infrastructure as part of the main site.yml playbook. It ensures consistent base configuration across all managed systems.
+
+## Dependencies
+None - this is a foundational role that other roles can depend on.
+
+## Notes
+This role is designed to be lightweight and provide only the most essential common functionality. Server-specific configurations should be handled by dedicated roles like `docker` or `bootstrap`.