Add ZED camera to Rexrov model

[AVSurfer123]

Use the provided package https://github.com/stereolabs/zed-ros2-wrapper and add it to the sub model

[AVSurfer123]

Can't use the ZED SDK due to this problem stereolabs/zed-ros-wrapper#190, so we instead will just use the ZED 3D frame with the built in Gazebo Kinect depth camera

[PERPETU4L-M0TI0N]

Tutorial Links:
http://gazebosim.org/tutorials?tut=ros_gzplugins&cat=connect_ros
http://gazebosim.org/tutorials/?tut=ros_depth_camera
http://gazebosim.org/tutorials?tut=ros_urdf&cat=connect_ros
https://docs.ros.org/en/foxy/Tutorials/URDF/Using-URDF-with-Robot-State-Publisher.html
http://gazebosim.org/tutorials?tut=ros_depth_camera&cat=connect_ros