Recursive discovery with /list
When running /list on a non-MUC service, the list of available services is shown, e.g. for `/list yax.im` the list contains anon.yax.im and chat.yax.im. When pressing on the latter, poezio tries to join chat.yax.im, and apparently succeeds.
However, it would be much better if poezio would detect that the node is not a MUC but a service, and to perform a disco#list on that, replacing the current list view with that of the selected node's items.