Adds atmos helpers, welding tool now lights up fires

Content.Server/Atmos/AtmosHelpers.cs

@@ -0,0 +1,25 @@
+using Content.Server.GameObjects.EntitySystems;
+using Robust.Shared.GameObjects.Systems;
+using Robust.Shared.Map;
+
+#nullable enable
+
+namespace Content.Server.Atmos
+{
+    public static class AtmosHelpers
+    {
+        public static TileAtmosphere? GetTileAtmosphere(this GridCoordinates coordinates)
+        {
+            var gridAtmos = EntitySystem.Get<AtmosphereSystem>().GetGridAtmosphere(coordinates.GridID);
+
+            return gridAtmos?.GetTile(coordinates);
+        }
+
+        public static TileAtmosphere? GetTileAtmosphere(this MapIndices indices, GridId gridId)
+        {
+            var gridAtmos = EntitySystem.Get<AtmosphereSystem>().GetGridAtmosphere(gridId);
+
+            return gridAtmos?.GetTile(indices);
+        }
+    }
+}