add dispatch filesystem

[martindurant]

Like open/open_files, which find the file-system of interest and use it with parameters, could implement a generic top-level file-system which finds the correct instance and use it depending on the protocol implicit in the path given. This would become the primary user-facing API.

This can also be the place to implement globs or recursive where multiple files make sense.

Should allow copy/move/(sync?) between file-systems.

[d4l3k]

This would be very helpful to have. Specifically having methods for file put/get without having to create a filesystem via fsspec.get_fs_token_paths would be very convenient.