Makes Airtight ECS. (#4351)

* Makes Airtight ECS.

* Remove atmos holdovers while at it!

Content.Server/Atmos/Commands/AddUnsimulatedAtmosCommand.cs

@@ -0,0 +1,62 @@
+using Content.Server.Administration;
+using Content.Server.Atmos.Components;
+using Content.Shared.Administration;
+using Robust.Shared.Console;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Map;
+
+namespace Content.Server.Atmos.Commands
+{
+    [AdminCommand(AdminFlags.Debug)]
+    public class AddUnsimulatedAtmosCommand : IConsoleCommand
+    {
+        public string Command => "addunsimulatedatmos";
+        public string Description => "Adds unimulated atmos support to a grid.";
+        public string Help => $"{Command} <GridId>";
+
+        public void Execute(IConsoleShell shell, string argStr, string[] args)
+        {
+            if (args.Length < 1)
+            {
+                shell.WriteLine(Help);
+                return;
+            }
+
+            if (!int.TryParse(args[0], out var id))
+            {
+                shell.WriteLine($"{args[0]} is not a valid integer.");
+                return;
+            }
+
+            var gridId = new GridId(id);
+
+            var mapMan = IoCManager.Resolve<IMapManager>();
+
+            if (!gridId.IsValid() || !mapMan.TryGetGrid(gridId, out var gridComp))
+            {
+                shell.WriteLine($"{gridId} is not a valid grid id.");
+                return;
+            }
+
+            var entMan = IoCManager.Resolve<IEntityManager>();
+
+            if (!entMan.TryGetEntity(gridComp.GridEntityId, out var grid))
+            {
+                shell.WriteLine("Failed to get grid entity.");
+                return;
+            }
+
+            if (grid.HasComponent<IGridAtmosphereComponent>())
+            {
+                shell.WriteLine("Grid already has an atmosphere.");
+                return;
+            }
+
+            grid.AddComponent<UnsimulatedGridAtmosphereComponent>();
+
+            shell.WriteLine($"Added unsimulated atmosphere to grid {id}.");
+        }
+    }
+
+}