Odom: Get odometry data from drivetrain in sim

[nico-palmar]

Publish nav_msgs/Odometry to the /odom topic coming from differential drive controller from ros2, which assumes twist message is being published to cmd_vel topic (to get the drivetrain to move).

According to: https://control.ros.org/master/doc/ros2_controllers/diff_drive_controller/doc/userdoc.html, the differential drive plugin with publish an odometry message. We just need to verify that this works correctly.

This should be a very short task (it should pretty much just work if the previous one works).