Add void

This time — with plot and upgrades.

The Void is a place where physicists study Cosmic Microwave Background, it is in the middle of nowhere for a reason. There are also people who believe something strange about listening the Universe and trying to tell it something. They are weird, but useful as a workforce… jeejah can be obtained here because that's a small version of CMB receiver; also you can buy a transmitter, screamer.

Some subnet discussion added so that a player has a reason to wonder what goes on in The Void. The story about this portal is not too clear.

Usefulness for testing deep-space-flight scripts is purely incidental.

This could solve #107 (closed)