XMPP

Describe the bug
When a form, sent via an adhoc command, contains a field named "username", it is not displayed at all.

Expected behavior
username is a valid field name, so the form should be displayed

Environment:

• Desktop
• Firefox
• Converse.js version [e.g. 4.2.0]

Additional context
I commented a minimal example here: https://github.com/conversejs/converse.js

For the feature Private key transfer #1090 you use Barcodes for verification.
Would it be a good idea to use the same way to verify Public key of contacts and mark this verificated users in contactlist with a green Icon or somewhat (similar to Threema )?

Maybe:
-yellow for "I'm not sure but I trust the key anyway and will verify it by our next beer."
-green for "I have scanned the code of m