Improved scalability of uploads using presigned URLs with S3

[lucabfelix]

@EduardoJM
To make the widget not only beautiful but also scalable in Django applications, an excellent solution is to use presigned URLs. With them, the upload is done directly from the browser to S3, without going through the Django server - Django role is limited to generating the secure URL for the client.

This approach drastically reduces the use of CPU, memory and bandwidth on the server, making the system faster, more economical and scalable. Since the files are sent directly to S3, it is possible to handle thousands of simultaneous uploads without overloading the backend. S3 itself manages the concurrency, eliminating the need to expand the application infrastructure.

[EduardoJM]

The use of presigned URLS of S3 is a good feature, but i don't have intentions to integrate it to this project for now.