Adds extended gamemode preset

Content.Server/GameTicking/GamePresets/PresetExtended.cs

@@ -0,0 +1,17 @@
+using System.Collections.Generic;
+using Robust.Server.Player;
+
+namespace Content.Server.GameTicking.GamePresets
+{
+    public class PresetExtended : GamePreset
+    {
+        public override string Description => "No antagonists, have fun!";
+        public override string ModeTitle => "Extended";
+
+        public override bool Start(IReadOnlyList<IPlayerSession> readyPlayers, bool force = false)
+        {
+            // We do nothing. This is extended after all...
+            return true;
+        }
+    }
+}

Content.Server/GameTicking/GameTicker.cs

@@ -487,6 +487,7 @@ namespace Content.Server.GameTicking
                 "traitor" => typeof(PresetTraitor),
                 "traitordm" => typeof(PresetTraitorDeathMatch),
                 "traitordeathmatch" => typeof(PresetTraitorDeathMatch),
+                "extended" => typeof(PresetExtended),
                 _ => default
             };