Direct control of light source exported values

Currently light sources export with a value based directly on their intensity, but this doesn't translate well into game mechanic lighting values.

For example, a torch in DnD5e emits bright light to 20ft and dim light for an additional 20ft, but making a torch that exports with a 20ft light radius in DA is impossible, even at the highest intensity (at least using a wall torch to test), and no dim light radius is ever created at all.

Instead of tying these number to the in-engine light source intensity, please allow them to be manually specified for export so that rules-correct light sources can be added.