Replicate FLOPS VAPPR behaviour

Desired capability or behavior.

Aviary should add functionality to replicate the FLOPS VAPPR behavior.

This is an input variable in FLOPS which allows the user to add an upper bound constraint on the value of output VAPP. VAPP appears in the Objectives/Variables/Constraints Summary section of FLOPS output file:

VAPP most closely maps to Mission.Landing.INITIAL_VELOCITY.

Suggested implementation.

Aviary could replicate the VAPPR behavior by adding a new constraint variable to the hierarchy (e.g. Mission.Constraints.MAX_APPROACH_VELOCITY), and then add a constraint:

Mission.Landing.INITIAL_VELOCITY <= Mission.Constraints.MAX_APPROACH_VELOCITY

When the value of Mission.Constraints.MAX_APPROACH_VELOCITY is greater than zero.

The FLOPS input variable AERIN.VAPPR should be mapped to this new variable (Mission.Constraints.MAX_APPROACH_VELOCITY) and handled by fortran_to_aviary conversion function.
An investigation should be conducted to see if there is an equivalent GASP variable that can also be mapped to this.
The new constraint should be made available for all problem types and equations of motion in Aviary.