Create a minimal example with partial derivatives

[chrbertsch]

It would be great to have a minimal example with directianal derivatives.

One could e.g. use the LinearTransform example. There trivially the Jacobian is just the Matrix A; so one can easily provide dirictionalderivatives by multiplying with A.

And I would like to extend this for the adjoint derivatives modelica/fmi-standard#722.

Is this possible?