Download of avatars and item images

[Bouni]

Find a nicer way of fetching and persisting the avatar images as well as the product images.

Currently users and products are created via django admin pages which prvide a field for a image URL:

When the container is restarted, we call two functions 1 2 that serach the database for fields that contain a URL, fetch that image and replace the value in the database with the path to the fetched image.