Add heating tower from space age as standalone, the tech require chemical science pack, it's a natural upgrade to boiler, it's a nice middle tech between boiler and nuclear if you exclude solar, require space age DLC as its use graphics and code from the DLC.
Current Cost
```lua
heating_tower_tech.prerequisites = { "chemical-science-pack" }
heating_tower_tech.unit = {
count = 250,
ingredients = {
{ "automation-science-pack", 1 },
{ "logistic-science-pack", 1 },
{ "chemical-science-pack", 1 }
},
time = 60,
}
```
