Move in-memory session storage to the separate directory of `storage`. It is
done for future support of different kind of session storages.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
In previous implementation session Storage.Get method took a v2 owner
identifier as an argument.
Change method signature to as an argument owner identifier from NeoFS SDK.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
