* Change publishers to publish unique ptrs

* Revert test case modification

* Update function signature to receive unique_ptrs

* Update publishers in nav2_costmap_2d to publish unique ptrs

* Update publishers in nav2_planner and nav2_map_server

* Change nav2_map_server publisher to publish occupancy grid unique ptr

* Change publisher in nav2_planner to publish path unique ptr

* Remove smart pointer return from functions in nav2_costmap_2d

* Run cpp_lint manually in nav2_costmap_2d

* Minor fixes

* Adhere to conventions of smart pointers passing to function

* Change publisher in dwb_core to publish unique pointer