Get/Set Transform Service Improvements

[allenh1]

I changed the names of the transform setters to be set_sensor_to_vehicle_translation and set_sensor_to_vehicle_rotation so that both the direction and the specific component of the transform is made a bit more clear.

I also added a service that returns the full device-stored transform (both translational and rotational) in a way that they could be directly republished in a geometry_msgs::TransformStamped from a client node.

On that note, I attemped to use the getSensorToVehicleRotation_quaternion(), but this is apparenlty not supported by my device (3DM-GX5-45). This seems rather odd, since it appears to be stored as a quaternion internally. I can remove the tf2::convert and the setRPY calls in the get_sensor_to_vehicle_transform function if that command is supported, which would clean up this patch a bit (though this can be done in a follow up).

Tested with the following (run in succession):

$ rosservice call /gx5/set_sensor_to_vehicle_translation "offset:
  x: 1.0
  y: 0.0
  z: 0.0" 
success: True

$ rosservice call /gx5/set_sensor_to_vehicle_rotation "angle:
  x: 1.5707963
  y: 0.0
  z: 0.0"
success: True

$ rosservice call /gx5/get_sensor_to_vehicle_transform 
translation: 
  x: 1.0
  y: 0.0
  z: 0.0
rotation: 
  x: 0.7071067966408575
  y: 0.0
  z: 0.0
  w: 0.7071067657322372
success: True

Please let me know if you need any adjustments/style changes, I'm more than happy to do so.