Implements REST storage and API server integration for MachineAccountKey resources

[JoseSzycho]

Summary

Implements REST storage and API server integration for MachineAccountKey resources, enabling full CRUD operations through the Kubernetes API.

Warning

This PR is paused, and will be completed on the next sprint

Changes

• ✅ Add REST storage provider for MachineAccountKey resources
• ✅ Integrate Milo-specific OpenAPI definitions with Kubernetes API server
• ✅ Enhance scheme registration with internal known types
• ✅ Add development configurations for local testing
• ✅ Generate OpenAPI definitions for IAM resources
• ✅ Update package naming from resourcemanager to iam
• ✅ MachineAccountKey creation with RSA key generation and validation of public keys
• 📝 Add local development instructions to README