Can't redirect nomad-pack output

As mentioned in #163, it's not possible to redirect nomad-pack's output. While #168 partially solves the issue for render, it still doesn't allow for instance capturing `info` output.

Also worth noting that even for render, just because it can output multiple files isn't a reason not to support redirection. If the user can get something output on stdout, they would expect to be able to redirect it like anything else.

Review the context in issues #163 and #168 first to understand the existing render behavior and the requested output semantics. Trace how nomad-pack commands emit render and info output, then define completion as allowing users to redirect supported stdout output, including info and render output that may span multiple files.

Written by the indexing model from the issue text.