developers should be able to sort uploads lists

[travis]

since we support pagination, we should also support sorting of some sort. it's a bit unspec'd exactly what we'd let people sort by, so I'm opening this issue to start tracking ideas and implementation.

inspired by a conversation with @alanshaw

My instinct was that this list should be timestamp sorted, but actually if you look at most other KV stores (including S3/R2) there is no way to list items other than lexicographically by key. So it’s unfortunate, but not inconsistent. I want to get to a place where we can build an abstraction on top of this allowing users to pick keys and sort them according to their requirements. It could just be a library, but it could also be used by w3console!