AtmosDevices can optionally process in space. (#4405)

Refactors some misc atmos things, too.

Content.Server/Atmos/Components/IAtmosphereComponent.cs

@@ -0,0 +1,12 @@
+using Robust.Shared.GameObjects;
+
+namespace Content.Server.Atmos.Components
+{
+    public interface IAtmosphereComponent : IComponent
+    {
+        /// <summary>
+        ///     Whether this atmosphere is simulated or not.
+        /// </summary>
+        bool Simulated { get; }
+    }
+}