Conditional map support (#5868)

Co-authored-by: E F R <602406+Efruit@users.noreply.github.com>
Co-authored-by: Paul Ritter <ritter.paul1@googlemail.com>

Content.Server/Maps/GameMapCondition.cs

@@ -0,0 +1,11 @@
+using Robust.Shared.Serialization.Manager.Attributes;
+
+namespace Content.Server.Maps;
+
+[ImplicitDataDefinitionForInheritors]
+public abstract class GameMapCondition
+{
+    [DataField("inverted")]
+    public bool Inverted { get; }
+    public abstract bool Check(GameMapPrototype map);
+}