We do consolidate them all to one method, at least, that was the intent of the select_hub function.

The check for the explicit string "default" that's used here is only to support the following command-line
    zenflow hubs describe default

Honestly, though, we can probably take this command out, as you can just as easily do
    zenflow hubs describe github.com

At one point, the default hub could be over-ridden, so having this extra command seemed useful.  But not so much anymore.