Fix s3 proxy New Folder button

[mathis-marcotte]

New folders aren't being shown in the UI after being created with the New Folder button, but only when accessing s3proxy through the service directly(with s3proxy-web/s3/namespace/).
The issue is because s3 doesnt display empty directories. To circumvent this, a function was put in place in the service worker js to create an empty file with newly created folders.
And the reason this bug is happening is because the service worker is not being registered in the service. This seems to be because the s3proxy service runs in an unsecure context, but you need a secure context (https) to be able to use service workers.

So to fix this, we could move the logic that creates the empty file out of the service worker. Although if we could possibly list empty directories without the need for a .empty file, that would be the best case scenario for sure.

[mathis-marcotte]

The logic for creating the empty files in new folders has been moved from the service worker code to the general js code so that it can always work.