Support for reading SICDs directly from cloud storage about sarpy HOT 1 CLOSED

Hi Kris, this has come up recently in another context, and a plan will be formulated in the immediate future. I need to have a discussion with some other interested parties to understand their use case and requirements before planning a path forward.

A difficulty for reading from and writing to S3 or other other cloud storage is that the fundamentals for accessing the image data currently relies on using a numpy.memmap, which in turn uses the native Python mmap implementation. This uses fundamentals of the file system, and requires an actual file. smart_open (or the like) returns a file-like object, but this is insufficient for the current approach for file reading and writing.

from sarpy.