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/Deeds/HolidayTreeDeed.cs

@@ -103,7 +103,6 @@ public partial class HolidayTreeDeed : Item
 
     public override void OnDoubleClick(Mobile from)
     {
-        from.CloseGump<HolidayTreeChoiceGump>();
         from.SendGump(new HolidayTreeChoiceGump(from, this));
     }
 }
@@ -113,6 +112,8 @@ public class HolidayTreeChoiceGump : Gump
     private readonly HolidayTreeDeed m_Deed;
     private readonly Mobile m_From;
 
+    public override bool Singleton => true;
+
     public HolidayTreeChoiceGump(Mobile from, HolidayTreeDeed deed) : base(200, 200)
     {
         m_From = from;