Fixes for APCs (from dev), fix for solars area, and simple APC load balancing

* A few critical fixes for APCs that were merged into dev after the merge to dev-freeze. The commits are identical, not copies, so I think it should be fine to merge them to dev-freeze also.
* Implements rudimentary load balancing for APCs in power nets. If power went unused last tick the powernet will raise the perapc quota each tick. APCs that have very low power draw still try to charge even when there is an overall deficit, but it's not a terrible problem.
* Fixed the missing fore solars control room area, and updated the (external) solars areas to match area/space a bit more. Fixes #6100. One thing I would like to get feedback on is that external solar areas have lighting_use_dynamic set to 0 but area/space has that set to 1. I'm thinking either one or the other should have that changed, but I'm not sure which one.