* Stop migrationg to MSC4278 if the config exists.
* Run migration after we have synced the client.
* Setup the SettingsController with a client.
* Add tests to check migration behaviour.
* update copyright
* Wait for sync properly
* Catch failure
* Docs
* licence
* Inline async code
* Fix migrateURLPreviewsE2EE too
* drop an import
* go away