[minor] Adds support for mirroring the MAS CLI image through the mas mirror-images

[PalVala]

Summary

Adds support for mirroring the MAS CLI image through the mas mirror-images workflow.

Changes

• adds --mirror-cli to non-interactive argument parsing
• includes CLI mirroring in mirror_everything()
• adds interactive prompting for CLI mirroring and CLI version selection in mirror_to_registry_interactive()
• validates the requested CLI version against Quay.io via validate_cli_version()
• exports MIRROR_CLI and CLI_VERSION for downstream mirroring
• shows CLI selection in the confirmation summary and executes mirror_cli
• documents the new flag in mirror_to_registry_help()

Why

Issue #600 requested a dedicated --mirror-cli option so users can mirror the CLI image as part of the existing image mirroring flow instead of handling it manually.

Testing

• verified --mirror-cli is accepted in non-interactive mode
• verified interactive flow prompts for CLI mirroring and version input
• verified invalid versions are rejected and valid versions are accepted by validate_cli_version()
• verified help output includes the new option in mirror_images_help

ansible-devops PR: ibm-mas/ansible-devops#2328