elp_stereo_camera with point cloud for ros2

ROS2 camera driver for the ELP stereo camera, tested with ROS Jazzy and the ELP-USB3D1080P120-H120 model. Original drivers from @heikoe

Added a file to create a point cloud.

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USAGE

Start the Camera

ros2 launch elp_stereo_camera stereo_camera_launch.py

Start the point cloud

ros2 run elp_stereo_camera stereo_point_cloud_generator