In previous implementation object.Search services allowed to search only
physically stored objects. This limitation did not allow getting the ID of
the split object.
Extend search execution logic with parent object filtering. Parent objects
that passed filters are now included in the result
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Use key storage in object services in order to sign requests with private
session key within user session.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
