Add support for reading and writing WFDB files in cloud containers

[briangow]

Functions like rdrecord expect a direct path to a file be passed. Cloud services typically use URIs to point to files stored in cloud containers. When working in the cloud, simply passing the URI to functions like rdrecord will not work. A filesystem interface is required to handle backend requirements (like authentication and protocols).

Packages such as pandas and dask use fsspec. This filesystem interface allows using the same functions to read files from local, remote, or embeeded file systems.

We should consider integrating fsspec or something similar into the WFDB software.