Integrate ZED with hardware and navigation launch files

[5yler]

From the ZED ROS wrapper wiki page:

The ZED Stereo Camera is a lightweight depth camera based on passive stereo vision. It outputs up to 2208x1242 high-resolution stereo video on USB 3.0, and can work in high-speed mode in VGA at 100 FPS. The ZED SDK computes a depth map of the environment on the GPU of the host machine at the frame rate of the camera. It also gives you access to a strong odometry that learn its environment, making it able to relocate itself at any moment.

Tasks

• [x] add ZED launch file to gigatron_hardware
• [ ] integrate ZED odometry with ekf_map.launch
• [x] create launch file for rtabmap_ros RGB-D SLAM

[5yler]

Relevant tutorials for ZED integration with rtabmap_ros:

• Stereo Hand-Held Mapping This tutorial shows how to use rtabmap_ros out-of-the-box with a stereo camera in mapping mode or localization mode.
• Setup RTAB-Map on Your Robot! This tutorial shows multiple RTAB-Map configurations that can be used on your robot.

The former has info on setting up localization with a stereo camera like the ZED, the latter covers integration with other sensors on a mobile platform.

[5yler]

I think the ZED point cloud frame is set wrong in zed.launch. Double check and update as appropriate.