S3 file support

[scottstanie]

Opening a meta issue for possible changes/additions to better support interacting with files on S3

• We might need something like s3path (but smaller) to interact with the filenames... using pathlib.Path('s3://my-bucket') leaves you with Path(s3:/my-bucket).
• rasterio has built-in support for strings like s3://my-bucket/my-file.tif, while using gdal bindings requires you to convert it to /vsis3/my-bucket/my-file.tif. That sounds annoying enough to find all edge cases that it might be worth the slow switchover to rasterio
• Probably a separate bigger issue related to the reader issue, but it would be useful to have hdf5 streaming capability