Map pool cvar (#12313)

* it just works

* nuke votable

* whoops

Content.Shared/CCVar/CCVars.cs

@@ -184,6 +184,12 @@ namespace Content.Shared.CCVar
         public static readonly CVarDef<string>
             GameMap = CVarDef.Create("game.map", "Saltern", CVar.SERVERONLY);
 
+        /// <summary>
+        ///     Prototype to use for map pool.
+        /// </summary>
+        public static readonly CVarDef<string>
+            GameMapPool = CVarDef.Create("game.map_pool", "DefaultMapPool", CVar.SERVERONLY);
+
         /// <summary>
         ///     Controls if the game should obey map criteria or not. Overriden if a map vote or similar occurs.
         /// </summary>