Previously, Messenger was `Start`ed multiple times, which resulted in
the shutdown process not being invoked on previously initialized
Messenger's sub-instances. This led to the failure of MVDS instance
shutdown causing massive error logs due to the attempts to read from a
closed database.
This is the second step of improvements over keypairs/keycards/accounts.
- `SyncKeycardAction` protobuf removed
- `SyncKeypair` protobuf is used for syncing keycards state as well as for all
keycards related changes
- `last_update_clock` column removed from `keypairs` table cause as well as
for accounts, any keycard related change is actually a change made on a related
keypair, thus a keypair's clock keeps the clock of the last change
- `position` column added to `keypairs` table, needed to display keycards in
the same order accross devices
This commit renames few api endpoints:
- old `AddMigratedKeyPairOrAddAccountsIfKeyPairIsAdded` renamed to `AddKeycardOrAddAccountsIfKeycardIsAdded`
- old `GetAllMigratedKeyPairs` renamed to `GetAllKnownKeycardsGroupedByKeyUID`
- old `GetMigratedKeyPairByKeyUID` renamed to `GetKeycardByKeyUID`
- old `DeleteKeypair` renamed to `DeleteAllKeycardsWithKeyUID`