Automatic XMPP address

[Hezkore]

Describe the bug

More of a feature, but I'd like to have converse.js automatically login the user.
Converse.js already supports this in converse.initialize() with the jid value, I just don't know how to fetch the current user's email.

If anyone can tell me how to fetch the user's primary mail, I'll sort this myself.

Context

• Hardware: Home server
• YunoHost version: 11.2.14
• Converse.js version: 10.1.4~ynh1

Steps to reproduce

• vim /var/www/converse/index.html
• Scroll down to converse.initialize
• Visit https://conversejs.org/docs/html/configuration.html#authentication for information about auth and jid
  • Please note that jid also works with authentication: 'login', not just prebind

Expected behavior

When the user visits converse.js, their primary email should be written in the "XMPP Address" field.