Rework sensor alignment

[digitalentity]

Alignment concept needs to be reworked.

We expect sensor alignment to be relative to the board which makes sense, but we then align board relative to the aircraft together with all of the sensors.

The consequence is that if you mount the board vertically (i.e. align_board_roll = 900) you need to rotate your external compass 90 deg as well, essentially mounting the GPS on the side, which doesn't make sense.

We need to be able to specify whether the sensor is internal or external, allowing us to specify sensor alignment relative to board (internal) or airframe (external).

[digitalentity]

What we need:

• For GYRO & ACC: hardcoded_sensor_alignment -> board_alignment
• For internal compass: sensor_alignemt -> board_alignment
• For external compass: sensor_alignemt
• For optic flow: sensor_alignment

This will bring all the sensor data into UAV frame of reference, regardless of board position.

[b14ckyy]

If we get Optical Flow sensor added to the alignment tool I think we have all covered?