Signed-off-by: Kurt Roeckx <kurt@roeckx.be>

The conversion between the two is now direct and thus shouldn't lose the state_keys.

- power level content override adds to the default event instead of
replacing it
- sending code refactored to make edus possible
- remove presence events when restarting conduit
- remove room_id field from read receipts over /sync
- handle incoming read receipts
- fix array bounds bug in server_server.rs

this also reverts some stateres changes

TIL body.device_id != (*body).device_id, which is pretty bad, so I
renamed body.device_id to body.sender_device