Add offset vectors from bounding box center to middle of front / rear axle

Author: Soyka-zz

osi_object.proto

@@ -54,6 +54,13 @@ message Vehicle
     /// The id of the driver of the (ego) vehicle.
     /// Field need not be set if ego_vehicle is set to false.
     optional Identifier driver = 10;
+    
+    /// The vector pointing from the bounding box center point (base.position) to the middle of the rear axle.
+    optional Vector3d bbcenter_to_rear = 11;
+
+	/// The vector pointing from the bounding box center point (base.position) to the middle of the front axle.    
+	optional Vector3d bbcenter_to_front = 12;
+    
 
     /// Definition of vehicle types.
     enum Type