The 3rd item of `Delete` container notification event is a byte array of
serialized session token. Parse session token in `ParseDelete` function.
Provide `Delete.SessionToken` method.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Neo-go does not use smartcontract.Parameter to return values
anymore, so it's convertes partly removed from neofs-node.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
