Allow admins to change round preset.

Content.Server/GameTicking/GamePresets/PresetSandbox.cs

@@ -0,0 +1,10 @@
+namespace Content.Server.GameTicking.GamePresets
+{
+    public sealed class PresetSandbox : GamePreset
+    {
+        public override void Start()
+        {
+            // Nothing yet.
+        }
+    }
+}

Content.Server/GameTicking/GamePresets/PresetTraitor.cs

@@ -1,12 +0,0 @@
-using Robust.Shared.Log;
-
-namespace Content.Server.GameTicking.GamePresets
-{
-    public class PresetTraitor : GamePreset
-    {
-        public override void Start()
-        {
-            Logger.DebugS("ticker.preset", "Current preset is traitor.");
-        }
-    }
-}