[#146] sdk/object: Move well-known header const to object type

Extended ACL filters and object search filters use strings to specify
well-known object headers, such as owner id, object id, etc. To unify
these constant they've been moved into object package, because they
specifying object related headers.

This should be noted in nspcc-dev/neofs-spec#12

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/acl/eacl/record_test.go

@@ -4,6 +4,7 @@ import (
 	"crypto/ecdsa"
 	"testing"
 
+	"github.com/nspcc-dev/neofs-api-go/pkg/object"
 	v2acl "github.com/nspcc-dev/neofs-api-go/v2/acl"
 	"github.com/nspcc-dev/neofs-crypto/test"
 	"github.com/stretchr/testify/require"
@@ -62,7 +63,7 @@ func TestRecord_AddFilter(t *testing.T) {
 	filters := []Filter{
 		{
 			from:    HeaderFromObject,
-			name:    HdrObjSysNameCID,
+			name:    object.HdrSysNameCID,
 			matcher: MatchStringEqual,
 			value:   "ContainerID",
 		},