Use enums for indices in controller_ros.h

[mortenfyhn]

I suggest replacing

  const uint8_t WRENCH_SURGE = 0;
  const uint8_t WRENCH_SWAY  = 1;
  const uint8_t WRENCH_HEAVE = 2;
  const uint8_t WRENCH_ROLL  = 3;
  const uint8_t WRENCH_PITCH = 4;
  const uint8_t WRENCH_YAW   = 5;

  const uint8_t POSITION_SURGE = 0;
  const uint8_t POSITION_SWAY  = 1;
  const uint8_t POSITION_HEAVE = 2;

  const uint8_t EULER_YAW   = 0;
  const uint8_t EULER_PITCH = 1;
  const uint8_t EULER_ROLL  = 2;

with three enum declarations inside the class.

[PeterAaser]

https://camo.githubusercontent.com/956360d829b049085b77cd8dcdb25c4e1288622f/68747470733a2f2f7261776769742e636f6d2f74616261746b696e732f62696b65736865642f6d61737465722f646f63732f69636f6e2e737667

[mortenfyhn]