The new algorithm is simpler. Instead of tracking a list of
disambiguated display names in `Room`, we instead track the display name
ambiguity status in `RoomMember`. This allows a client to generate the
correct name for a member using solely the information available in
`RoomMember`.
The disambiguation algorithm itself now only calculates the set of members
whose ambiguity status had changed instead of producing disambiguated
display names for everyone affected. This is called on each room entry
(join or invite), room entry and profile change, and the updates are
propagated to the affected `RoomMember`s.
Ruma can't currently handle an event with the wrong event content type.
When replacing the MessageEventStub's content it automatically
serializes as "m.room.redaction".
The client objects in the sdk accepted an optional session argument at
creation time. If provided this would restore the client into a logged
in state.
Since we need to restore the client state and encryption state at some
point it makes sense to do it when the client transitions into a logged
in state. At the same time we would like to avoid the client creation to
be async.
This introduces a restore_login() method which can be called instead of
the login() method to restore a session.
