Differential and ackermann using angular speed architectures not implemented yet.
Added a pointcloud publisher of the collision points.

Migrated to PointCloud2 (not operational yet).
Migrated to TF2.

Added modes: front_rear, original independent front/rear laserscan usage, frame_check, new mode where laserscans are transformed to base_frame pointclouds, and its points are used separately for front o rear speed limit
Added unsafe joy button, where a defined joy button enables unsafe mode while pressed

- optimitzada funcio de calcul maxim vel
- manicura de codi (usar _ enlloc de this-> ...)
- Testejat amb simulacio teo_sim

 - added parameters for variables
 - if a scan is not received, outputs an error (but keeps working)

Saturation to max front and rear velocities computed from distance to closer obstacle. Also relative motion command from teleop.

IRI SAFE CMD: filter cmd_vel depending on Laser Scans, so the robot stops moving to a close object. To be used with teleop or non-OA navigation