this also reverts some stateres changes

The latest state-res crate uses ruma's PduRoomV3 PDU's which don't have
tuples of (EventId, EventHashs) like previous versions did (this was
left from rebasing onto master). The Media DB
now takes an optional content_type like the updated ruma structs.

Log entries will automatically be deduplicated, so a message won't be
sent if the same line has already been sent in the last 30 mins

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

See https://matrix.org/docs/spec/client_server/r0.6.1#id87

It can be enable in the Rocket.toml config or using ROCKET_FEDERATION_ENABLED=true