[#1953] engine: Add refactored storage helpers

After the refactor there are new storage characteristics: a type and
a general storage id (that could be stringified).

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

pkg/local_object_storage/internal/log/log.go

@@ -24,3 +24,13 @@ func AddressField(addr interface{}) zap.Field {
 func OpField(op string) zap.Field {
 	return zap.String("op", op)
 }
+
+// StorageTypeField returns logger's field for storage type.
+func StorageTypeField(typ string) zap.Field {
+	return zap.String("type", typ)
+}
+
+// StorageIDField returns logger's field for storage ID.
+func StorageIDField(id []byte) zap.Field {
+	return zap.String("storage_id", string(id))
+}