improve (s3): support for prefixes with > 1k objects (#395)
improve (s3): support for prefixes with > 1k objects (#395)

Previously filestash would only show the first 1000 objects in a given
s3 prefix.

We solve this by paginating the ListObjectsV2 responses and iterating
over all pages instead of just the first one.

Tested by manually connecting to a private s3 bucket with multiple
thousands of objects under a single prefix and verifying that all
objects are visible in the UI.
mickael-kerjean/nuage,mickael-kerjean/nuage,mickael-kerjean/nuage,mickael-kerjean/nuage,mickael-kerjean/nuage,mickael-kerjean/nuage