Implemented System Heat for the stock drills' asteroid and comet modes (modules?).

[Ryan-Gorley]

• Created ModuleSystemHeatCometHarvester.cs, equivalent to ModuleSystemHeatHarvester.cs

  • Changed SystemHeat.csproj to include ModuleSystemHeatCometHarvester.cs

• Changed ModuleSystemHeatAsteroidHarvester.cs to match ModuleSystemHeatHarvester.cs

• Changed SystemHeatDrill.cfg to implement system heat for asteroid and comet modules for both stock drills

• Added an empty line in ModuleSystemHeatHarvester.cs for consistency.

Issue: https://github.com/post-kerbin-mining-corporation/SystemHeat/issues/66