Create documentation

[lukicdarkoo]

The packages (especially epuck_ros2_cpp) are missing detailed documentation. Readme files such as the following two should be created:

• https://github.com/cyberbotics/webots_ros2/tree/epuck2/webots_ros2_epuck2
• https://github.com/cyberbotics/epuck_ros2/tree/master/epuck_ros2_camera

[lukicdarkoo]

A huge amount of content required for the documentation can be shared with webots_ros2_epuck: https://github.com/cyberbotics/webots_ros2/blob/master/webots_ros2_epuck/README.md

How do we handle this? Do we copy and change the specific details, or we create common documentation + documentation specific to webots_ros2_epuck and epuck_ros2_cpp separately?

[omichel]

We should never copy as the copies will inevitably diverge at some point. The best is to document at one place and set a pointer to this documentation from the other place(s).