RenderInfantry refactoring

Removes `RenderInfantryProne` and `RenderInfantryPanic` traits, and moves that "react when attacked" behavior into `RenderInfantry` itself. An interface called `IReactOnAttack` was added and both `TakeCover` and `ScaredyCat` traits implement it. Those classes were also cleaned up as well.

I think there's 5 upgrade scenarios in total and rules were created. Needed to be careful not to mess with Spy though.
```
Rules:
	ProneActor:
		-RenderInfantry:
		RenderInfantryProne:
			IdleAnimations: idle1, idle2
	PanicActor:
		-RenderInfantry:
		RenderInfantryPanic:
			IdleAnminations: idle1, idle2
	NewProneActor:
		RenderInfantryProne:
			IdleAnminations: idle1, idle2
	NewPanicActor:
		RenderInfantryPanic:
			IdleAnminations: idle1, idle2
	LeaveThisSpyAlone:
		-RenderInfantry:
		RenderDisguise:
			IdleAnimations: idle1, idle2
```

becomes

```
	ProneActor:
		RenderInfantry:
			IdleAnimations: idle1, idle2
	PanicActor:
		RenderInfantry:
			IdleAnminations: idle1, idle2
	NewProneActor:
		RenderInfantry:
			IdleAnminations: idle1, idle2
	NewPanicActor:
		RenderInfantry:
			IdleAnminations: idle1, idle2
	LeaveThisSpyAlone:
		-RenderInfantry:
		RenderDisguise:
			IdleAnimations: idle1, idle2
```
I'm not 100% convinced on this name.  Something like `IRenderInfantrySequenceModifier` would make the purpose more explicit.