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>
Replace UnaryHandler from structure to method arguments in order to reuse
single instance for different service methods.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>