Change all publishers to publish unique ptrs

[SteveMacenski]

From experiments shown in ros-drivers/ros2_ouster_drivers#41, we see that when publishing unique pointers rather than raw messages themselves, there is a substantial decrease in litter in the system.

We should transition all ROS publishers in navigation (and anywhere we can) to this method. This is especially important for topics publishing larger messages like pointclouds, maps, and images.