feat: Moves gumps out of the core (#1916)

> [!Important]
> **Developer Note**
> This code change will **completely move gumps out of the core**


### Summary

- Adds `GetGumps()` convenience which exposes methods to Find/Close/Send multiple gumps. This helper is a performance improvement by eliminating the Dictionary<Player, List> lookup for gumps.

Projects/UOContent/Engines/Quests/Core/QuestObjective.cs

@@ -130,6 +130,8 @@ namespace Server.Engines.Quests
     {
         private readonly QuestSystem m_System;
 
+        public override bool Singleton => true;
+
         public QuestLogUpdatedGump(QuestSystem system) : base(3, 30)
         {
             m_System = system;