Tracking issue for fuel cell electric vehicles

Tracking issue to list notes/problems that need to be fixed before fuel cell vehicles will work in FASTSim-3

• Internally we will handle a fuel cell vehicle as a HybridElectricVehicle, but add a new PowertrainType option FuelCellElectricVehicle(Box<HybridElectricVehicle>)
• New powertrain type and inner struct:

  pub enum PowertrainType {
      // ...
      #[serde(rename = "FCEV")]
      #[serde(alias = "FuelCellElectricVehicle")]
      FuelCellElectricVehicle(Box<FuelCellElectricVehicle>),
  }
  

• Copy series HEV logic into new FuelCellElectricVehicle inner struct
• Why not reuse HybridElectricVehicle?
  • No generator for FCEVs, FuelConverter supplies electrical power
    • No need to allow None generator for Series hybrids for just the FCEV case
  • HEVPowertrainControls options do not apply to FCEV
  • HEVAuxControls may still apply, dunno yet

FuelType added by PR #259 (issue #289) will be useful for this, it already has a Hydrogen variant

Blockers:

• #283
  • almost same topology as series hybrid, but FC supplies electrical power directly to RES/EM/aux(?) instead of through a generator
  • adding a series hybrid will teach a lot about FASTSims inner workings and is the same core logic
• #306
• #286
• After these, create a new struct FuelCellElectricVehicle