Get Bucket file list.

{
  "message": "successful operation",
  "data": [
    {
      "key": "new-object"
    },
    {
      "key": "second-file.txt"
    }
  ]
}

{
  "message": "You have to be authorized to access this resource."
}

{
  "message": "Access denied for user."
}

{
  "message": "Bucket not found."
}