Add mini-map to options menu

Not very intuitive to activate the mini-map just using M. Surely, that’s a nice shortcut, but I think we should also add it to the options section of the menu for clarity.

I knew the mini-map had been implemented but I couldn’t find it anywhere. Had to ask players to tell me I need to hit M. Since the game doesn’t have a manual, the menu should include all commands like that.