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/Gumps/Go/GoGump.cs

@@ -25,10 +25,10 @@ public class GoGump : Gump
 
     private readonly LocationTree _tree;
 
+    public override bool Singleton => true;
+
     private GoGump(int page, Mobile from, LocationTree tree, GoCategory node) : base(50, 50)
     {
-        from.CloseGump<GoGump>();
-
         if (node == tree.Root)
         {
             tree.LastBranch.Remove(from);