Add comprehensive ECS+ALB CloudFormation template test

Adds a test suite that validates parsing a realistic CloudFormation
template containing:
- ECS Cluster with container insights
- ECS Task Definition with Fargate configuration
- ECS Service with load balancer integration
- Application Load Balancer with listener and target group
- Security groups for ALB and ECS tasks
- IAM roles for task execution and task
- CloudWatch Log Group
- Application Auto Scaling (conditional on environment)

The tests verify:
- All 11 resource types can be dynamically generated and parsed
- Complex nested properties (NetworkConfiguration, ContainerDefinitions)
- All CloudFormation intrinsic functions (Ref, Fn::Sub, Fn::GetAtt,
  Fn::Join, Fn::If)
- Conditional resources and properties
- Resource attributes (DependsOn, Condition)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: jsoucheiron