Provide backup data if loading from S3 is slow

[nmdefries]

Occasionally it takes a really long time (1 min vs the normal 15-20s) to load input data from the S3 bucket. This problem can be seen in both staging and public dashboards at the same time, which indicates that it is an AWS or network problem rather than a bug in our code. Can load fallback data if directly loading from AWS takes longer than [x] seconds.