expose entire spikeball config as properties

[varnholt]

      struct SpikeConfig
      {
         // factor to control the push force when ball moves from right to left
         float _push_factor = 0.625f;

         // number of points retrieved from the given spline
         int32_t _spline_point_count = 25;

         // chain element setup
         int32_t _chain_element_count = 10;
         float _chain_element_distance = 0.3f;
         float _chain_element_width = 0.06f;
         float _chain_element_height = 0.0125f;
      };