Layering for atmospheric pipes (#36124)

Co-authored-by: ArtisticRoomba <145879011+ArtisticRoomba@users.noreply.github.com>
Co-authored-by: Kevin Zheng <kevinz5000@gmail.com>

Content.Shared/Atmos/EntitySystems/SharedAtmosPipeAppearanceSystem.cs

@@ -0,0 +1,18 @@
+using Content.Shared.Atmos.Components;
+
+namespace Content.Shared.Atmos.EntitySystems;
+
+public abstract partial class SharedAtmosPipeAppearanceSystem : EntitySystem
+{
+    /// <summary>
+    /// Returns the max number of pipe layers supported by a entity.
+    /// </summary>
+    /// <param name="uid">The entity being checked.</param>
+    /// <param name="atmosPipeLayers">The entity's <see cref="AtmosPipeLayersComponent"/>, if available.</param>
+    /// <returns>Returns <see cref="AtmosPipeLayersComponent.NumberOfPipeLayers"/>
+    /// if the entity has the component, or 1 if it does not.</returns>
+    protected int GetNumberOfPipeLayers(EntityUid uid, out AtmosPipeLayersComponent? atmosPipeLayers)
+    {
+        return TryComp(uid, out atmosPipeLayers) ? atmosPipeLayers.NumberOfPipeLayers : 1;
+    }
+}