Implement 'drasi ingress install contour' CLI command

[Copilot]

This PR implements a new CLI command drasi ingress install contour to automate the deployment of the Contour ingress controller in Kubernetes clusters using Helm.

Features

The new command provides:

• Nested command structure: drasi ingress install contour following existing CLI patterns
• Helm integration: Uses the official Bitnami Contour chart with proper error handling
• Flexible configuration: Supports custom Helm values via YAML files
• Namespace management: Configurable installation namespace with sensible defaults
• Readiness verification: Optional waiting for deployment completion
• Permission validation: Checks cluster permissions before installation

Command Options

drasi ingress install contour [flags]

Flags:
  -f, --config-file string   Path to custom Helm values file
  -n, --namespace string     Namespace to install Contour into (default: projectcontour)
  -w, --wait                 Wait for Contour to be ready before returning

Usage Examples

# Basic installation
drasi ingress install contour

# Install with custom configuration
drasi ingress install contour --config-file values.yaml --namespace ingress-system --wait

Implementation Details

• Follows existing CLI architecture patterns from commands like init and namespace
• Integrates with the SDK's KubernetesPlatformClient for cluster operations
• Uses Helm v3 client library for chart management (same as Dapr installation)
• Includes comprehensive error handling with helpful user messages
• Provides detailed help documentation and usage examples
• Added unit tests for YAML configuration loading and value merging
• Maintains consistency with existing output formatting and task reporting

Testing

• All existing tests continue to pass
• New unit tests cover configuration file handling
• Manual testing verified command structure and help output
• Error handling tested for common failure scenarios

The implementation seamlessly integrates with the existing Drasi CLI while providing the requested Contour installation automation.

Fixes #300.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.