Add throttle as an output or ability to constrain it in solved groundroll phase

[johnjasa]

Desired capability or behavior.

Some users (Jes) want to be able to constrain the throttle during the velocity-integrated groundroll phase currently used in the solved 2dof mission.
This phase currently assumes you're at full throttle for takeoff (I believe) and he was trying to evaluate performance if throttle was constrained at 0.9 but couldn't!
We could expose the notion of throttle in some way, maybe have it be solved for like the other phases in solved 2dof, and allow users to constrain it.

Is your feature request related to a problem? Please describe.

No response

Associated Bug Report

No response