feat: enhance cloudflared connector with HPA support and resource management

[wei840222]

#128

This PR introduces two key enhancements to the cloudflared connector management:

🚀 Features

1. HPA (Horizontal Pod Autoscaler) Support

• Flexible replica management: When CLOUDFLARED_REPLICA_COUNT < 0, the controller will not modify deployment replicas
• HPA compatibility: Allows users to configure autoscaling using HPA without controller interference
• Backward compatibility: Existing configurations continue to work as expected

2. Resource Requirements Management

• Dynamic resource configuration: Add support for CLOUDFLARED_RESOURCES environment variable
• JSON-based configuration: Configure CPU/memory limits and requests via JSON format
• Runtime resource updates: Controller detects and applies resource changes automatically

3. Code Quality Improvements

• Remove duplicate code: Replace custom slicesEqual function with Go's built-in slices.Equal
• Better command handling: Rename buildCloudflaredCommand to getCloudflaredCommand for clarity
• Enhanced error handling: Improved error management and code structure
• Null safety: Add proper nil checks for replica counts

🔧 Technical Changes

Files Modified:

• pkg/controller/controlled-cloudflared-connector.go: Core logic enhancements
• pkg/controller/controlled-cloudflared-connector_test.go: Updated tests and removed obsolete test cases

Key Improvements:

1. Deployment Logic Refactoring: Streamlined deployment creation and update logic
2. Resource Detection: Added automatic detection of resource requirement changes
3. Command Comparison: Enhanced command argument change detection
4. Memory Management: Better handling of deployment specifications

📋 Usage Examples

Enable HPA support:

env:
  - name: CLOUDFLARED_REPLICA_COUNT
    value: "-1"  # Disable replica management

Configure resources:

env:
  - name: CLOUDFLARED_RESOURCES
    value: '{"requests":{"cpu":"100m","memory":"128Mi"},"limits":{"cpu":"500m","memory":"512Mi"}}'

This enhancement provides more flexibility for users who want to manage cloudflared deployments with advanced Kubernetes features while maintaining simplicity for basic use cases.