Include progress bar when uploading data

[dalonsoa]

Uploading big data files to the data base and parsing them can take a significant amount of time. A progress bar - or other mechanism - should be implemented to inform the user that something is going on.

Maybe we can get inspiration from here:

• https://www.freecodecamp.org/news/how-to-build-a-progress-bar-for-the-web-with-django-and-celery-12a405637440/

Aha! Link: https://imperial-college-ict.aha.io/requirements/RSE-138-8