Add celestial bodies from the most common mods that add new planets like OPM

[Attila1616]

If it's possible add dV stats to mods that add other planets, or add the ability to use custom dV readouts for custom planets like alexmoon's launch window planner.

[Blaarkies]

Related to #12

This would be great. It would need the loading/unloading of mods to do this, and maybe even being able to publish that so that other users may use that mod pack without building out the details themselves.