- fixed use of history_d deferred so MAM history is stored in database as soon as possible
and in right order
- get MAM history with pages of 20 messages instead of 100
- if a message can't be parsed, an error message is logged (with a dump of the stanza),
and the message is ignored, avoiding a crash and the impossibility the join the room at
all
- a new `mucRoomPrepareJoin` signal, containing room jid and profile, is sent when a room
joining is started, this allow better UX as the frontend can show the room immediately,
and lock it with a waiting message until it is fully available. The `mucRoomJoined` is
still sent when the room is fully joined/avaiable, meaning that the frontend can unlock
it and let the user interact with it
f065ba4ff6