Show history of maximum power generation in electric network graph

[macdjord]

The electric network window shows a history of power production and consumption, as well as accumulator charge level. But the power production graph only shows the actual power generation, not the maximum power generation available. Having a history of that would be very helpful for things like spaceships (where solar generation capacity changes as they move) or Fulgoran bases (where it would be real nice to know how much potential energy is available from your lightning rods).