mod_http_oauth2: Implement RFC 8628 Device Authorization Grant Meant for devices without easy access to a web browser, such as refrigerators and toasters, which definitely need to be running OAuth-enabled XMPP clients! Could be used for CLI tools that might have trouble running a http server needed for the authorization code flow.

This module writes out a traceback to `traceback.txt` in Prosodys data
directory (see `prosodyctl about`) when the signal `SIGUSR1` is
received. This is useful when debugging seemingly frozen instances in
case it is stuck in Lua code.