[MapFeatures] Add and Edit Planet Settings

The MapFeatureEditor should allow the user to view default planets added by the map and edit their features and resources, along with the ability to disable existing atmospheres and add new ones (both Sphere and Cuboid). This will allow a much less statically defined way of making questionable maps work correctly, as well as being able to edit in atmospheric resources (like Humidity, CO, Methane, etc.) as need be rather than just having the gamemode dumbly add them in to everything.

TODO:

• Auto-collate MapFeature entries per detected atmosphere.
• Add new planets/atmospheres.
  • Spherical
  • Cuboid
  • Stars?
• Override saving for planet settings.
• Atmosphere disablement (remove sc_planet object).