Converted all vehicles from spawning sub-entities to simply including them in their base prefab heirarchy. Converted:
- Duo Sub [fuel storage, torpedo storage, item storage]
- Hot Air Balloon [fuel storage, item storage]
- Magnet Crane [fuel storage]
- Minicopter (in earlier commit) [fuel storage]
- MLRS [dashboard storage, rocket storage]
- Modular car chassis [fuel storage]
- RHIB [fuel storage, item storage]
- Rowboat [fuel storage, item storage]
- Scrap Transport Helicopter [fuel storage]
- Solo Sub [fuel storage, torpedo storage, item storage]
- Work Cart [fuel storage]
All fuel-using vehicles also now start with 50 fuel when in editor.