Retry uploads and queuing uploads

If you are offline and take a bunch of photos (maybe you're on holiday / flakey internet), it'd be good to save those images and queue them for retry when the internet is back. Maybe display a 'no connection' icon on the upload, then automatically retry them when you're back in the app?

Maybe post-mvp feature.

But we definitely need a way to retry / delete broken uploads (they just stay on the camera screen at the moment). Might tie into #13.

Start by reviewing the camera screen's current upload flow and issue #13 to understand how broken uploads are represented. Define the scope for offline queuing, automatic retry, and retry or delete actions; done should include a clear way to recover or remove failed uploads and, if included, retry them after connectivity returns.

Written by the indexing model from the issue text.