Entity ghost of roboports show preview connections and areas

[DoubleThought]

When building a roboport network, especially when roboports are just unlocked, it is very important to make sure that they connect as intended. However, when placing roboport ghosts, it's very difficult to tell if two roboport ghosts are close enough together that when they're built, they'll be in the same network. Currently, the way I do it is I place a roboport ghost, wait however long it takes for the next roboport item to be crafted and placed, and then place the next roboport ghost. This is, for obvious reasons, inconvenient. It's worse than not having an underground belt helper, because it's far enough that I can't simply just eyeball the distances involved.