Remove `Object` and `RawObject` types from `pkg/core/object` package.
Use `Object` type from NeoFS SDK Go library everywhere. Avoid using the
deprecated elements.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
All parameters and resulting values of all metabase operations are
structured in new types. The most popular scenarios for using operations are
moved to auxiliary functions.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>