Check the status of a task to fetch/upload a file from a URL

The endpoint notifies about the progress of the task by changing the value of the status field:

• the field is set to waiting initially
• once the system starts processing the request, the field is set to progress
• if the file is fetched and uploaded successfully, the status field is set to success and the endpoint returns a JSON object holding information about the uploaded file
• if the system fails to fetch/upload the file, the status field is set to error and the error field is set to the cause of the error.