backend, frontend: prepare remote control: This is a series of changes necessary to prepare the implementation of remote control feature: - XEP-0166: add a `priority` attribute to `ApplicationData`: this is needed when several applications are working in a same session, to know which one must be handled first. Will be used to make Remote Control have precedence over Call content. - XEP-0166: `_call_plugins` is now async and is not used with `DeferredList` anymore: the benefit to have methods called in parallels is very low, and it cause a lot of trouble as we can't predict order. Methods are now called sequentially so workflow can be predicted. - XEP-0167: fix `senders` XMPP attribute <=> SDP mapping - XEP-0234: preflight acceptance key is now `pre-accepted` instead of `file-accepted`, so the same key can be used with other jingle applications. - XEP-0167, XEP-0343: move some method to XEP-0167 - XEP-0353: use new `priority` feature to call preflight methods of applications according to it. - frontend (webrtc): refactor the sources/sink handling with a more flexible mechanism based on Pydantic models. It is now possible to have has many Data Channel as necessary, to have them in addition to A/V streams, to specify manually GStreamer sources and sinks, etc. - frontend (webrtc): rework of the pipeline to reduce latency. - frontend: new `portal_desktop` method. Screenshare portal handling has been moved there, and RemoteDesktop portal has been added. - frontend (webrtc): fix `extract_ufrag_pwd` method. rel 436

=============================
identity: identity management
=============================

Identity use several XMPP extensions (like vcards) to retrieve or set informations about
an entity. For now it's really basic and only nickname and avatar are managed.

get
===

Retrieve informations about the identity behind an XMPP entity. You only have to specify
the jid of the entity, and you'll get (if set) his/her/its nickname and data about the
avatar.

When available, cached values are returned by defaut. If you want to ignore the cache, use
the ``--no-cache`` option (of course this can result in more network requests).

example
--------

Get identity information about an entity::

  $ li identity get somebody@example.org

set
===

Set identity data to the server, using various XMPP extensions. So far, you can only
change the nickname of an entity using ``-n, --nick`` or or more times

example
-------

Set 2 nicknames for default profile::

  $ li identity set -n toto -n titi