Update reference line type according new osi version

OSI 3.7 has 2 type for coordinate system:

1. TYPE_POLYLINE
2. TYPE_POLYLINE_WITH_T_AXIS

ReferenceLine in OSI 3.7 has field type to specify type of coordinate system.

The goal of this MR is to match map-sdk implementation and OSI 3.7 for type ReferenceLine

include/MapAPI/reference_line.h

@@ -27,8 +27,15 @@ struct ReferenceLinePoint
 
 struct ReferenceLine
 {
+  enum class Type : std::uint8_t
+  {
+    TYPE_POLYLINE = 0,
+    TYPE_POLYLINE_WITH_T_AXIS = 1
+  };
+
   Identifier id{UndefinedId};
-  std::vector<ReferenceLinePoint> poly_line;
+  std::vector<ReferenceLinePoint> poly_line{};
+  Type type{Type::TYPE_POLYLINE};
 };
 }  // namespace map_api