feat: Add native CLI support for cluster lifecycle management

[PrasadJoshi12]

Summary

Currently, ocpctl only supports cluster management via the Web UI and REST API.
There is a placeholder noted in the codebase (cmd/cli/ — "not implemented")
but no CLI binary exists yet.

Motivation

A native CLI would improve the developer experience significantly for:

• Interactive use without needing a browser
• Shell scripting and local automation without raw curl wrappers
• Faster feedback loop during development/testing

Proposed Interface

# Authentication
ocpctl login --url https://api.ocpctl.example.com
ocpctl login --iam   # AWS IAM-based auth

# Cluster management
ocpctl cluster create --name my-cluster --platform aws --type openshift \
  --version 4.22.0 --profile aws-sno-test --region us-west-2

ocpctl cluster list
ocpctl cluster get <cluster-id>
ocpctl cluster delete <cluster-id>
ocpctl cluster hibernate <cluster-id>
ocpctl cluster resume <cluster-id>

# Pool operations
ocpctl pool list
ocpctl pool lease <pool-name> --duration 2h
ocpctl pool release <cluster-id>

# Output formats
ocpctl cluster list -o json
ocpctl cluster list -o yaml