Allow taking map screenshot

[evildogbot100]

TL;DR

Allow a script to take screenshot of the game map (the pixelated map, not the game surface)

What ?

Exactly as the title and tldr

Why ?

At some point, megafactories or gigafactories, taking screenshot of your whole factory really obscures the detail and most machines look a bit same-ish from crazy zoom level. At this point it makes a bit more sense to just screenshot the map, it even contains some information that are invisible from the game surface like electric network and logistic network. Besides it doesn't seem to be a huge feature to get worked on but it helps with documentation of factories.