* sync preferred name;
remove settings.usernames
* update account name when handle settings.preferred_name from backup message
* fix Error:Field validation for 'KeycardPairingDataFile' failed on the 'required' tag
* bump version
* rebase
- Display name is now backed up only as a part of `protobuf.BackedUpProfile` message,
it is not backed up via `protobuf.SyncSetting` any more (this refers only to backing up to
and fetching data from waku, regular syncing (among devices) remains unchanged)
- When saving the display name fetched from waku, before a clock was set to the current
time when that operation is made, which was incorrect, now we're using the clock from
backed up message (`SaveSyncDisplayName` function)
Changes applied here introduce backing up profile data (display name and identity
images) to waku and fetch them from waku. Information about those data is sent
as a separate signal to a client via `sync.from.waku.profile` signal.
New signal `sync.from.waku.progress` is introduced which will be used to notify a client
about the progress of fetching data from waku.
