Add CLI deployment command group

## Overview

Add CLI commands for Deployment management in backend.ai client.

## Tasks

1. Create `deployment` command group in client CLI:
- `backend.ai deployment create` - Create new deployment
- `backend.ai deployment list` - List deployments
- `backend.ai deployment info ` - Show deployment details
- `backend.ai deployment update ` - Update deployment
- `backend.ai deployment delete ` - Delete deployment
1. Add options for filtering, pagination, output format (json/table)
1. Implement proper error handling and user feedback
1. Write CLI tests

## Reference

- Existing CLI commands in src/ai/backend/client/cli/

JIRA Issue: BA-3433