We don't use custom names and the only place where custom method option
is used it provides the default name and can be omitted.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
`Delete` method of latest `Container` contract accepts binary session token
as an argument.
Provide `DeleteArgs.SetSessionToken` method. Accept session token as a
`[]byte` in `Wrapper.Put` method and attach it to `PutArgs`. Marshal session
token from `RemovalWitness` in `wrapper.Delete` function and pass it to the
method.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
