DuckPAN should warn about, or not follow redirects for API calls (to mimic our NGINX)

[moollaza]

We've run into issues with NGINX related to HTTP APIs that redirect to HTTPS or API calls that first return a 302 and point elsewhere.

DuckPAN currently follows these without problems, but our NGINX setup does not.

To aid developers, we should point this out to them so they notice ahead of time