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/Items/Skill Items/Thief/DisguiseKit.cs

@@ -102,14 +102,14 @@ public class DisguiseGump : Gump
     private readonly DisguiseKit m_Kit;
     private readonly bool m_Used;
 
+    public override bool Singleton => true;
+
     public DisguiseGump(Mobile from, DisguiseKit kit, bool startAtHair, bool used) : base(50, 50)
     {
         m_From = from;
         m_Kit = kit;
         m_Used = used;
 
-        from.CloseGump<DisguiseGump>();
-
         AddPage(0);
 
         AddBackground(100, 10, 400, 385, 2600);