[submod] Empty space (base facility)

[Kozinsky]

This submod adds a new base module, the "Empty space", which can be used to prepare space before building all other modules. Any other base facilities placed on top of the "empty space" will be built five days faster than if it were placed on an unprepared surface.
Dismounting modules now takes some time. And after disassembling a module, there will be an "empty space" in its place.

[Bananas_Akimbo]

Really good idea. This will make redesigning the first base much easier. It will also speed up the creation of new bases with chokepoints, but at a slightly higher cost. I will try it, once I get to play again.