Plane: Quadplane flight modes pitch trim

[IamPete1]

Add independent trim functionality when in Quadplane flight modes

Introduced Q_AHRS_TRIM_X, Q_ AHRS_TRIM_Y and Q_AHRS_TRIM_Z these allow quadplane view to be rotated with respect to forward flight view. Quadplanes can then be trimed for forward flight in the usual way, and also trimed sperarly for vertical flight.

Trim is in radians to match overall trim, trim is relative to forward flight trim, requires reboot to take effect.

I'm abit of a C++ noob so not sure if this is the most efficient method of doing this, does work tested on PH1

[IamPete1]

I have changed this such that it is only pitch trim as discussed in the dev call.

I attempted to make it update on the calibrate level command as for forward flight, I couldn't get it to work in the end. I added

if (!quadplane.in_vtol_mode()) { // trim forward flight ahrs.set_trim(Vector3f(trim_roll, trim_pitch, 0)); } else { // trim vtol pitch quadplane.quadplane_ahrs_trim_pitch.set_and_save(trim_pitch); }

to Plane::accel_cal_update()

but no luck, it wasn't even not updating the the forward flight trim in Q modes, not to sure why this is.

[tridge]

I've rebased on master and done some small cleanups on this. When this passes CI I think it's ready to go in. Thanks Peter!