[#140] object: Support LOCK type

Add `TypeLock` value to `Type` enum. Implement `Lock` type compatible
with corresponding message. Implement `ObjectLocked` and
`IrregularObjectLock` errors in `apistatus` package.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

client/status/object.go

@@ -0,0 +1,66 @@
+package apistatus
+
+import (
+	"github.com/nspcc-dev/neofs-api-go/v2/object"
+	"github.com/nspcc-dev/neofs-api-go/v2/status"
+)
+
+// ObjectLocked describes status of the failure because of the locked object.
+// Instances provide Status and StatusV2 interfaces.
+type ObjectLocked struct {
+	v2 status.Status
+}
+
+func (x ObjectLocked) Error() string {
+	return errMessageStatusV2(
+		globalizeCodeV2(object.StatusLocked, object.GlobalizeFail),
+		x.v2.Message(),
+	)
+}
+
+// implements local interface defined in FromStatusV2 func.
+func (x *ObjectLocked) fromStatusV2(st *status.Status) {
+	x.v2 = *st
+}
+
+// ToStatusV2 implements StatusV2 interface method.
+// If the value was returned by FromStatusV2, returns the source message.
+// Otherwise, returns message with
+//  * code: LOCKED;
+//  * string message: "object is locked";
+//  * details: empty.
+func (x ObjectLocked) ToStatusV2() *status.Status {
+	x.v2.SetCode(globalizeCodeV2(object.StatusLocked, object.GlobalizeFail))
+	x.v2.SetMessage("object is locked")
+	return &x.v2
+}
+
+// LockNonRegularObject describes status returned on locking the non-regular object.
+// Instances provide Status and StatusV2 interfaces.
+type LockNonRegularObject struct {
+	v2 status.Status
+}
+
+func (x LockNonRegularObject) Error() string {
+	return errMessageStatusV2(
+		globalizeCodeV2(object.StatusLockNonRegularObject, object.GlobalizeFail),
+		x.v2.Message(),
+	)
+}
+
+// implements local interface defined in FromStatusV2 func.
+func (x *LockNonRegularObject) fromStatusV2(st *status.Status) {
+	x.v2 = *st
+}
+
+// ToStatusV2 implements StatusV2 interface method.
+// If the value was returned by FromStatusV2, returns the source message.
+// Otherwise, returns message with
+//  * code: LOCK_NON_REGULAR_OBJECT;
+//  * string message: "locking non-regular object is forbidden";
+//  * details: empty.
+func (x LockNonRegularObject) ToStatusV2() *status.Status {
+	x.v2.SetCode(globalizeCodeV2(object.StatusLockNonRegularObject, object.GlobalizeFail))
+	x.v2.SetMessage("locking non-regular object is forbidden")
+	return &x.v2
+}