OM Structure: Hydrogen control variable

[elenya-grant]

OM Structure: Hydrogen control variable

Update the framework so that hydrogen can be used as the control variable rather than power. This would require adding a component that can calculate curve-coefficients for a hydrogen-to-current curve and another component that can use those coefficients and has an input hydrogen signal. This would also require either:

• updating the scale-down components to work for hydrogen or power OR
• adding a new scale-down component to work for hydrogen