Create tutorial using SpaceNet L1B WorldView data stored in S3

[dshean]

The Atlanta dataset includes L1Bs in the metadata/10* directories. Unfortunately, these are not COGs.

We may want to create sample COGs for a few of these L1Bs and host in our own S3 bucket to test subsetting and performance.

There are orthoimages for Atlanta stored as COGs in the nadirXX_catid_10* directories, but these cannot be used for stereo processing.