Replace `ErrNotFound`/`ErrAlreadyRemoved` error from
`pkg/core/object` package with `ObjectNotFound`/`ObjectAlreadyRemoved`
one from `apistatus` package. These errors are returned by storage
node's server as NeoFS API statuses.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
There are certain errors which are not expected during usual node
operation and which tell us that something is wrong with the shard.
To prevent possible data corruption, move shard in read-only mode after
amount of errors exceeded some threshold. By default no actions are performed.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>