Compass: use_for_yaw  to use primary compass health

This allows the internal compass to be used if the external compass
fails.
Compass: use_for_yaw for each compass
Compass_PX4: primary compass based on use_for_yaw
Compass_VRBrain: primary compass based on use_for_yaw
Compass: add ORIENT2 and EXTERNAL2 params
Compass_PX4: use instance specific orient and external
Compass_VRBrain: use instance specific orient and external
Compass_HMC5843: use instance specific orient and external
Compass_HIL: use instance specific orient and external