Update sam_bot + first time setup guide for Modern Gazebo

[SteveMacenski]

• sambot description URDF/SDF and bridge for GZ
• Update Sensors, Odometry First Time Setup Guide for them
• Update with Tutorial for GPS with TB3 to modern GZ https://github.com/ros-navigation/navigation2_tutorials/tree/rolling/nav2_gps_waypoint_follower_demo

[Amronos]

I am willing to work on this issue! Expect some PRs in a few days.

[Amronos]

@SteveMacenski I am also going to be making a SDF file for the description, should the documentation for that be added here or should a separate tutorial be made?

[SteveMacenski]

Lovely, thanks! I think a new tutorial for the SDF is appropriate so we can make sure to not confuse folks up front and have the chance to introduce the idea of an SDF separately from the URDF. I think that tutorial should be between the URDF (so they have a basic robot description working) and the Setup Odometry (so that the SDF file exists already for them to add in the modifications for the drive train / sensor simulations)!

Thanks so much!