Rotate/Set Vessel reference heading

As the title and summary states this function would apply a transformation to the vessel's primary reference (Z+) axis.

The most common application of this function would be to change the reference heading of the default Autopilots. This would be useful in a variety of situations most notably for space tugs pushing asymetrical loads, and for Tail-sitters/Lunar Lander-type craft wherein the main engine's axis of thrust may not be along the Z+ axis.

Inspired by the ShiftCOG function I started writing a custom function for my Lunar Lander that would rotate the vessel in the global frame while applying a matching counter-transformation, to thrusters, docking ports and the like but the proscess is rapidly getting out of hand.

There should be an easier way to do this.

I imagine the function would look something like...