Add XEP-0215 in Server Informations window
Currently the "Server Information" window provides some XEP supported by the server for a given account.
I would suggest to add XEP-0215 External Service Discovery in the list, as it is relevant for Audio/Video chats (at least with Conversations, when #10109 will be implemented).
For information, Conversations provides this info in its "Server Information" window.