Wire download progress reporting through the CLI

[timlichtenberg]

Problem description

Downloads are silent; for multi-GB spectral files there is no indication that a fetch is progressing or stalled. The Fetcher accepts a progress option but the CLI does not expose it.

Preferred solution

A --progress option on fwl-io fetch (default on for a TTY, off otherwise), passed through to the fetchers.

[nichollsh]

This would be great. One option: https://tqdm.github.io/