Add radiators (#18728)

* Add radiators

* Limit heat transfer to fluid heat capacity

* Adjust datafield names

* Fix material arbitrage

* This code has been debugged, and so there are no more bugs. Debugging code is therefore unnecessary

* Adjust radiator layer subfloor visibility

* Cache CVars

* No default

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

* Like and unsubscribe

* Fix CVar caching

---------

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

Resources/Prototypes/Entities/Structures/Piping/Atmospherics/binary.yml

@@ -379,3 +379,45 @@
         acts: ["Destruction"]
   - type: Machine
     board: GasRecyclerMachineCircuitboard
+
+- type: entity
+  parent: GasBinaryBase
+  id: HeatExchanger
+  name: radiator
+  description: Transfers heat between the pipe and its surroundings.
+  placement:
+    mode: SnapgridCenter
+  components:
+  - type: Rotatable
+  - type: Transform
+    noRot: false
+  - type: Sprite
+    sprite: Structures/Piping/Atmospherics/heatexchanger.rsi
+    layers:
+    - sprite: Structures/Piping/Atmospherics/pipe.rsi
+      state: pipeStraight
+      map: [ "enum.PipeVisualLayers.Pipe" ]
+    - state: heStraight
+      map: [ "enum.SubfloorLayers.FirstLayer" ]
+  - type: SubFloorHide
+    visibleLayers:
+    - enum.SubfloorLayers.FirstLayer
+  - type: Appearance
+  - type: PipeColorVisuals
+  - type: AtmosDevice
+  - type: HeatExchanger
+  - type: NodeContainer
+    nodes:
+      inlet:
+        !type:PipeNode
+        nodeGroupID: Pipe
+        pipeDirection: North
+      outlet:
+        !type:PipeNode
+        nodeGroupID: Pipe
+        pipeDirection: South
+  - type: Construction
+    graph: GasBinary
+    node: radiator
+  - type: StaticPrice
+    price: 50