Merge `address` package into `oid` one. Bring `session.Object`
implementation into conformity with the NeoFS API protocol.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
This is done to prevent import cycles when `object` package needs any other
that requires `object.ID` or `object.Address`.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
