AC_AttitudeControl: Add conversions from cd to rad

[lthall]

This PR adds radian (_rad, _rads) variants of all input_XXX rate and attitude commands in AC_AttitudeControl. These functions mirror the existing centidegree-based (_cd, _cds) methods, enabling direct use of SI units or the addition of degrees.

This does add size:

After AC_AttitudeControl: Add conversions from cd to rad

Board,blimp,bootloader,copter,heli,plane,rover,sub
CubeOrange,*,*,-64,-32,24,*,-48

[rmackay9]

instead of using "* radians(0.01)" I'd prefer we create a new method called something like, "radians_from_cd(x)"

[tridge]

@rmackay9 maybe cd_to_rad() ?