Replaced sensor_msgs/PointCloud to sensor_msgs/PointCloud2 (#2263)

* converted PointCloud -> PointCloud2 adn checked linting. WIP

Signed-off-by: Sachin <sachin.guruswamy@gmail.com>

* modified base_obstacke_test

Signed-off-by: Sachin <sachin.guruswamy@gmail.com>

* Changed to PointCloudModifier WIP

* formating fix

Signed-off-by: Sachin <sachin.guruswamy@gmail.com>

* formating fix2

Signed-off-by: Sachin <sachin.guruswamy@gmail.com>

* added tests for clearing_endpoints

Signed-off-by: Sachin <sachin.guruswamy@gmail.com>

* removing print statements

Signed-off-by: Sachin <sachin.guruswamy@gmail.com>

* added subscribers for voxel marked and cost_cloud

Signed-off-by: Sachin <sachin.guruswamy@gmail.com>

* modified test cases to use single wait for all pointcloud2 subscribers

Signed-off-by: Sachin <sachin.guruswamy@gmail.com>

* removed unnecessary comments and publish_cost_grid_pc from yaml file

Signed-off-by: Sachin <sachin.guruswamy@gmail.com>

* Fix ament_flake issues

Signed-off-by: Sachin <sachin.guruswamy@gmail.com>