`tt status` supports JSON and YAML output formats

The tt status command now supports multiple output formats:

• Table format (default, human-readable)
• JSON format (machine-readable, for automation)
• YAML format (machine-readable, for automation)

Usage:

• tt status - default table output
• tt status --format=json - JSON output
• tt status --format=yaml - YAML output

--pretty option is deprecated in favor of --format=pretty-table.

The JSON and YAML formats include all status information:

• Instance name
• Status (RUNNING, STOPPED, etc.)
• PID (if running)
• Mode (RW/RO)
• Config status
• Box status
• Upstream status
• Alerts (with severity levels)

Example JSON output:

{
  "app:master": {
    "status": "RUNNING",
    "pid": 12345,
    "mode": "RW",
    "config": "ready",
    "box": "running",
    "upstream": "--",
    "alerts": []
  }
}

Requested by @psergee in https://github.com/tarantool/tt/commit/dbfd762da7cba5d8600ea5dde9f82671aa9c0801.