[ROS] - Refactor RB-Pearl sensor tf

[rafa-martin]

Latest version for pearl, it publish points from base instead center of the sphere.

[RomanRobotnik]

@rafa-martin when you say last version, does it means that in the past was different?

[rafa-martin]

I would say, the version for this PR fixes the error I have.

[RomanRobotnik]

Can you check if it still works for simulation in the same way?

[rafa-martin]

No, it doesn't. It creates the rays from ${prefix}_link and isn't correct to start from base.
To keep backward compatibility, we can keep the same TF offset in urdf from ${prefix}_base_link. But:

1. In simultation poincloud will be ${prefix}_link as frame_id in header field.
2. In real, pointcloud message will be ${prefix}_base_link as frame_id in header field.

[rafa-martin]

Revert previous commit, format xacro and remove M_PI variable in favor to use radians function from xacro