Progress of vehicle damage system

#1122

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#### The Plan

- [x] Change `explosionEffect` to appropriate size/none at all for unarmed ground vehicles.
- [ ] ~~Enable passengers to survive vehicle destruction (except for explosions - although in modern tanks there are systems that keep the crew alive even in cook-offs, proven in Iraq by the M1s in service with the Iraqi Army)~~
- [x] Figure out a way to do ammo cook-off for tanks
- [x] Don't let tanks explode unless that cook-off is triggered
- [x] Increase the damage done to crew by kinetic penetrators etc. It should be possible to kill a tank crew without destroying the tank. (A hit to the front should usually kill or knock out the driver)
- [x] Add visual indicator of cook-off for people inside tank
- [x] Add sound ~~& light~~ for cook-off
- [x] Some heavy smoke coming out of the engine if you crash a car 
- [ ] ~~SLAM side attack explosion needs more boom! (kill crew) (#752)~~

Helicopters are fine for now, and jets are too (although there could be some visual improvements, but that's for another time).