config: @c ErrorCode refs for macro docs.
Datastore: added create_object(), destroy_object(), and generate_id().
config: added HORD_FMT_UNSCOPED().
IO::Datastore: added ErrorCode::datastore_prop_void for stream acquire.
test/common/DummyDatastore: corrected create_object_impl() prototype.
IO::Datastore: removed ErrorCode::datastore_prop_unsupplied from stream release.
IO: added PropTypes for auxiliary & scratch and their corresponding SerializationFlags.
IO: added get_prop_type_name().
Object: added get_type_name().
IO::Datastore: corrected disallowed copy & move traits.
IO::Datastore: made stream release check if datastore is locked before calling impl.