Address PR feedback and reorganize infrastructure as code tools article

- Convert to rank-ordered list (1-10) with Pulumi as #1 per Isaac feedback
- Reorganize sections to flow sequentially 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
- Remove lesser-known vendors (Atlantis, Vagrant, Docker Compose) per Eric feedback
- Strengthen competitive positioning vs Terraform (highlight BSL licensing)
- Add HashiCorp Sentinel to security tools list
- Reorder benefits list to improve flow (move drift to middle)
- Split Azure ARM and Bicep into separate sections per Isaac feedback
- Add prominent Pulumi call-to-action after section 1 instead of buried at end
- Update section headings to use "Key Features" consistently
- Add Pulumi ESC and Pulumi Insights sections per Eric request

Author: asafashirov