List instance type families

curl --request GET \
  --url https://cloud-api.phala.com/api/v1/instance-types

{
  "result": [
    {
      "name": "<string>",
      "items": [
        {
          "id": "<string>",
          "name": "<string>",
          "description": "<string>",
          "vcpu": 123,
          "memory_mb": 123,
          "hourly_rate": "<string>",
          "requires_gpu": true,
          "default_disk_size_gb": 20,
          "family": "<string>"
        }
      ],
      "total": 123
    }
  ]
}