Is your feature request related to a problem? Please describe.

1. Deploy a configuration that has a locked MUC domain, e.g. muc.example.org
2. Click Add a new groupchat
3. Enter a room address like room@muc.example.org
4. The @ gets escaped and Converse.js attempts to join room\40muc.example.org@muc.example.org

Describe the solution you'd like

If the input ends with

It’d be useful for users to know which version they’re running on.

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