discourse integration - Change Whonix forum software to discourse

[Patrick]

Forum login over .onion broken

Forum login over the .onion endpoint as of several days ago and today (2024-12-23) fails with “Unknown error” response. Clearnet works fine. POST request to the /session endpoint has response code 403 with raw body of ["BAD CSRF"] despite the X-CSRF-Token header having been included in the request.