Remove default RSS settings intended for Sol

"Empty" files to replace the asteroids and atmosphere gas settings from
RSS.  They have dummy modulemanager entries in them because KSP freaks
out when it runs into 0-byte configs.

This seems easier than telling people to delete these two files.

The CustomAsteroids config isn't compatible, and even says "Earth" in it. Anyone using Custom Asteroids might see some oddities if they leave this file in.

I don't think the RealHeat config is used by anything released yet, but its purpose is to change the atmosphere compositions of a few planets from the Kerbol system default to Sol system planets, so it needs to go.