Add ability to run displacement workflow with CSLCs on S3

[scottstanie]

Currently working to configure S3 urls, but stuck on a GDAL limitation: You can't (reliably) combine /vsis3 with the netcdf driver and a subdataset.

Wwe can read from one stack of HDF5 files with HDF5:..., but there will be no georeferencing information, meaning we can't combine multiple OPERA stacks.

Even if that gets working, there's probably still a few bugs to iron out with s3://... strings and subdatasets. But since it's a pretty sizeable blocker, I'm marking this as draft for now.