refactor(behavior_velocity_crosswalk_module): clean up the code (autowarefoundation#4157)

* refactor

Signed-off-by: Takayuki Murooka <takayuki5168@gmail.com>

* use tier4_autoware_utils's boost types

Signed-off-by: Takayuki Murooka <takayuki5168@gmail.com>

* return Point instead of Point2d

Signed-off-by: Takayuki Murooka <takayuki5168@gmail.com>

* remove unnecessary lambda function

Signed-off-by: Takayuki Murooka <takayuki5168@gmail.com>

* add Line2d in tier4_autoware_utils

Signed-off-by: Takayuki Murooka <takayuki5168@gmail.com>

* remove unnecessary member variable

Signed-off-by: Takayuki Murooka <takayuki5168@gmail.com>

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Signed-off-by: Takayuki Murooka <takayuki5168@gmail.com>

Author: takayuki5168

common/tier4_autoware_utils/include/tier4_autoware_utils/geometry/boost_geometry.hpp

@@ -34,6 +34,7 @@ using Box2d = boost::geometry::model::box<Point2d>;
 using LineString2d = boost::geometry::model::linestring<Point2d>;
 using LinearRing2d = boost::geometry::model::ring<Point2d>;
 using Polygon2d = boost::geometry::model::polygon<Point2d>;
+using Line2d = boost::geometry::model::linestring<Point2d>;
 using MultiPoint2d = boost::geometry::model::multi_point<Point2d>;
 using MultiLineString2d = boost::geometry::model::multi_linestring<LineString2d>;
 using MultiPolygon2d = boost::geometry::model::multi_polygon<Polygon2d>;