[Enhancement] Remove custom ROS2 camera node & CI

[Hoog-V]

Removal custom ROS2 camera node & CI

As listed in the TODO, I removed the custom ROS2 camera node and replaced it with v4l2_camera (see the gitlab repo).

This brings in several advantages:

1. Default implementation means easy to integrate with other ros2 packages
2. CI integration now tests whether the ROS2 code still compiles

The documentation has been updated to make sure it still runs.

[Hoog-V]

@ducroq when approved, merge it right away. Otherwise you can't test the face mesh package (as this is tied in as dependency on main branch!)

[ducroq]

looks great