Adds detailed documentation covering the new audit subsystem:
- Add new audit.md design document explaining:
- Core concepts and design decisions
- CQL extensions for audit management
- Implementation details and trigger evaluation
- Prior art references from other databases
- Add user-facing documentation:
- New auditing.rst guide with configuration and usage details
- Integration with security documentation index
- Updates to cluster management procedures
- Updates to security checklist
The documentation covers all aspects of the audit system including:
- Configuration options and storage backends (syslog/table)
- Audit categories (DCL/DDL/AUTH/DML/QUERY/ADMIN)
- Permission model and security considerations
- Failure handling and logging
- Example configurations and output formats
This ensures users have complete guidance for setting up and using
the new audit capabilities.
