[ARP] Fix follower stepper velocity

- Follower: the stepper velocity was saturating due to the fact that it was used the time as seconds while treated as in ms. This issue made saturate always the stepper velocities

[ARP] Follower now accept gain changes

- Follower: Now the gain can be changed externally from the SMA.
  This is done to change them in case of feedback and no-feedback states.
  Also, they are limited to a maximum of 1.0