conference: improve conference protocol for multi stream

The current design got some limitations. It's not possible to
control informations per shared media. This means that we can't
got several active sinks for example.
The goal of this patch here is to update the conferences orders
to be able to control the state of each sink individually and for
the client to be able to handle conferences with accounts connected
via several devices with several medias per devices.
So each orders is sent with a different level (account/device/media)

For example, we will be able to send a moderator order for an account,
to hangup a device or to set a media active.

To support those orders, both sides MUST be patched. Else, the old
protocol will be used. The version of the protocol supported is sent
in the conferences informations to notify the peer what version to use.

Finally, this patch changes some APIs to support multisteam:
+ Some APIs now takes the deviceId or the sinkId when necessary

jami-project#1429
Doc: https://git.jami.net/savoirfairelinux/jami-project/-/wikis/technical/6.1.-Conference-Protocol
Change-Id: Ieedd6055fd43b2a09b2cc8b253dcd6a3bf260a39