Modernize a bit

[annevk]

In particular:

• Depend more on Shepherd and less on the dated document internal database.
• Remove WebSocket section as fetch handles that.
• Move from a priori authenticated to potentially trustworthy.
• Drop the explicit port change as it would always no-op (default port for a scheme is normalized to null on a URL)
• Export the definition Fetch needs to invoke.

[annevk]

I think this fixes #11, #13, and #18.