message: isaac sim: updated instructions for 2022, added stereo option
diff: Note: carter_2dnav package can be copied to your catkin_ws from:
  $ cp -r ~/.local/share/ov/pkg/isaac_sim-2021.2.0/ros_workspace/src/* ~/catkin_ws/src/.
  + Isaac Sim 2021:
  For Lidar 3D Mode (lidar3d:=true), make sure in isaac sim that Carter robot is set with VLP16-like parameters (16 rings):
  Under World -> Carter_ROS -> chassis_link -> carter_lidar -> highLod = True
  -> verticalFov = 32
  -> verticalResolution = 2
  -> ROS_lidar -> pointCloudEnabled = True
  +
  + Isaac Sim 2022 (Action Graph):
  + To enable all camera streams (right, depth left and depth right):
  + 1. Stage view -> World-> Carter_ROS, right-click on ROS_Cameras -> Open graph
  + 2. For all Branch nodes (green/red icon), select them, then check Compute Node -> Inputs -> Condition checkbox.
  + 3D LIDAR: TODO: didn't find how to enable/publish it.
  -->
  <param name="use_sim_time" value="true" />
  <arg name="lidar3d_grid3d" default="true" />
  <arg name="camera" default="true" />
  + <arg name="stereo" default="false" /> <!-- RGB-D mode by default -->
  <!-- Load Robot Description -->
  <arg name="model" default="$(find carter_description)/urdf/carter.urdf"/>
  <arg name="localization" value="$(arg localization)"/>
  <arg if="$(arg lidar3d)" name="subscribe_scan_cloud" value="true"/>
  <arg unless="$(arg lidar3d)" name="subscribe_scan" value="true"/>
  - <arg name="depth" value="$(arg camera)"/>
  + <arg name="stereo" value="$(eval camera and stereo)"/>
  + <arg name="depth" value="$(eval camera and not stereo)"/>
  <arg name="subscribe_rgb" value="$(arg camera)"/>
  <arg name="visual_odometry" value="false"/>
  <arg name="odom_topic" value="/odom"/>
  <arg name="depth_topic" value="/depth_left"/>
  <arg name="rgb_topic" value="/rgb_left"/>
  <arg name="camera_info_topic" value="/camera_info_left"/>
  + <arg name="left_image_topic" value="/rgb_left"/>
  + <arg name="left_camera_info_topic" value="/camera_info_left"/>
  + <arg name="right_image_topic" value="/rgb_right"/>
  + <arg name="right_camera_info_topic" value="/camera_info_right"/>
  <arg name="scan_topic" value="/scan"/>
  <arg name="scan_cloud_topic" value="/point_cloud"/>
  <arg name="rgbd_sync" value="true"/>
  