FNSolarPanelWasteHeatModule: Added Megajoules handling with support for ...

...upgradable efficiency.

Adds logic to FNSolarPanelWasteHeatModule to produce megajoules from solar panels in lieu of electrical charge.  This is primarily useful for solar-powered IR scopes, which require megajoules for the helium cryostat.  Also has uses for low-altitude solar power sats.

As written this behaves identically to the current KSPI solar panels, except it produces kilowatt values of Megajoules instead of units of ElectricCharge.

I don't know for certain, but I think the resource system still requires some storage space.  Below is a ModuleManager config that adds Megajoules storage to solar panels.

```
@PART[*]:HAS[@MODULE[ModuleDeployableSolarPanel]]:NEEDS[WarpPlugin]:AFTER[WarpPlugin]
{
	RESOURCE
	{
		name = Megajoules
		amount = 0
		maxAmount = 10
		isTweakable = False
	}
}
```