Refactor Ansible playbooks to comply with best practices and fix linting violations

- Implement 4-role architecture (base_provision, patching, hardening, decommission)
- Extract hardcoded values to role defaults and group_vars
- Add Ansible Vault integration for secrets management
- Implement proper handlers for service restarts instead of direct tasks
- Add Molecule testing framework with Docker driver
- Configure ansible-lint with production profile settings

Fix all 125+ ansible-lint violations:
- Add FQCN (Fully Qualified Collection Names) to all modules
- Replace yes/no with true/false for boolean values
- Add explicit mode parameters to file/template operations
- Remove duplicate post_tasks blocks from playbooks
- Add newlines at end of all YAML files
- Fix key ordering in tasks (name, when, block)
- Convert service restarts to handlers with notify
- Remove ignore_errors in favor of failed_when/changed_when
- Fix line length violations and empty lines
- Add noqa comments for unavoidable risky-file-permissions

Update documentation:
- Add REFACTORING.md with implementation details
- Add VAULT_GUIDE.md for secrets management
- Add per-role README.md files
- Update existing documentation

All playbooks now pass ansible-lint production profile with 0 violations.

enterprise-infra-simulator/group_vars/databases.yml

@@ -0,0 +1,9 @@
+---
+# Database servers group configuration
+db_type: postgresql
+db_port: 5432
+db_backup_enabled: true
+db_backup_path: /var/backups/database
+
+# Database user (use vault for production)
+db_admin_user: postgres