Modify backup script to automatically upload downloaded entities to dev server #2568

For Issue #2568 

Oh I probably misunderstood the discussion on setting the live and dev server. 
This script handles backing up data, so it only goes from the live server to the dev server. The uploading to live server is handled by the [upload data script]( https://github.com/TEAMMATES/repo/blob/master/scripts/upload_data.py) created in #2447.