Atmos Debug Overlay expansion (#2626)

* Atmos Debug Overlay: Add a way of showing blocked directions

* Atmos Debug Overlay: Adjustable modes client-side

* Atmos Debug Overlay: Fix atvrange help text

* Atmos Debug Overlay: More flexible and clear gas ID specification

Content.Shared/Atmos/AtmosCommandUtils.cs

@@ -0,0 +1,28 @@
+#nullable enable
+using System;
+using Content.Shared.Atmos;
+
+namespace Content.Shared.Atmos
+{
+    public class AtmosCommandUtils
+    {
+        /// <summary>
+        /// Gas ID parser for atmospherics commands.
+        /// This is so there's a central place for this logic for if the Gas enum gets removed.
+        /// </summary>
+        public static bool TryParseGasID(string str, out int x)
+        {
+            x = -1;
+            if (Enum.TryParse<Gas>(str, true, out var gas))
+            {
+                x = (int) gas;
+            }
+            else
+            {
+                if (!int.TryParse(str, out x))
+                    return false;
+            }
+            return ((x >= 0) && (x < Atmospherics.TotalNumberOfGases));
+        }
+    }
+}