dont use wildcard allow origin header, allow credentials & send credentials on fetch
Created by: arussellsaw
This should be the final change, it's actually working already, but the browser still complains about CORS because of the headers returned. Specifically it doesn't like allowing a wildcard origin.
The reason it works is that we only really need the headers sent in the request, which are sent before it can determine if it's happy about CORS
we now use r.Host as the allowed origin, and include credentials on the request.