* Add tests for device list updates
* Add stale_device_lists table and use db before asking remote for device keys
* Fetch remote keys if all devices are requested
* Add display_name col to store remote device names
Few other tweaks to make `Server correctly handles incoming m.device_list_update`
pass.
* Fix sqlite otk bug
* Unbuffered channel to block /send causing sytest to not race anymore
* Linting and fix bug whereby we didn't send updated dl tokens to the client causing a tightloop on /sync sometimes
* No longer assert staleness as Update blocks on workers now
* Back out tweaks
* Bugfixes
* Add InputDeviceListUpdate
* Unbreak unit tests
* Process inbound device list updates from federation
- Persist the keys in the keyserver and produce key changes
- Does not currently fetch keys from the remote server if the prev IDs are missing
* Linting
* Add QueryDeviceMessages to serve up device keys and stream IDs
* Consume key change events in fedsender
Don't yet send them to destinations as we haven't worked them out yet
* Send device list updates to all required servers
* Glue it all together
* Fix New users appear in /keys/changes
* Create blank device keys when logging in on a new device
* Add PerformDeviceUpdate and fix a few bugs
- Correct device deletion query on sqlite
- Return no keys on /keys/query rather than an empty key
* Unbreak sqlite properly
* Use a real DB for currentstateserver integration tests
* Race fix
* Recheck device lists when join/leave events come in
* Add PerformDeviceDeletion
* Notify clients when devices are deleted
* Unbreak things
* Remove debug logging
