Gives the gas analyzer visual clues that it's open (#2110)

* Gives the gas analyzer visual clues that it's open

* Read Visualizer states from yaml

Content.Shared/GameObjects/Components/Atmos/SharedGasAnalyzerComponent.cs

@@ -0,0 +1,20 @@
+using Robust.Shared.Serialization;
+using System;
+
+namespace Content.Shared.GameObjects.Components.Atmos
+{
+    [NetSerializable]
+    [Serializable]
+    public enum GasAnalyzerVisuals
+    {
+        VisualState,
+    }
+
+    [NetSerializable]
+    [Serializable]
+    public enum GasAnalyzerVisualState
+    {
+        Off,
+        Working,
+    }
+}