Doesn't require a PIN like Telegram, as we can access a list of guild
users with the GuildMembers intent set. This has to be enabled under
Bot > Priviliged Gateway intents on the developer portal.
Discord, Email & Telegram can be enabled, although email is always
enabled right now (will fix). Also apparently markdown hyperlinks don't
work in Discord, eventually will implement something to convert them to
embeds.
The bot should be created by the admin and added to a discord server
mutual to the intended new user(s). On !start in the server,
communication is moved to DMs. Currently !start works, and validity of a
given PIN is checked although nothing it done with this yet.