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.Tests/Tests/Gumps/TestGumps/StaticLayoutTestGump.cs

@@ -0,0 +1,40 @@
+using Server.Gumps;
+
+namespace Server.Tests.Gumps;
+
+public class StaticLayoutTestGump : StaticGump<StaticLayoutTestGump>
+{
+    private readonly string _petName;
+
+    public StaticLayoutTestGump(string petName) : base(50, 50)
+    {
+        _petName = petName;
+        Serial = (Serial)0x123;
+        TypeID = 0x5345;
+    }
+
+    protected override void BuildLayout(ref StaticGumpBuilder builder)
+    {
+        builder.AddPage();
+
+        builder.AddBackground(10, 10, 265, 140, 0x242C);
+
+        builder.AddItem(205, 40, 0x4);
+        builder.AddItem(227, 40, 0x5);
+
+        builder.AddItem(180, 78, 0xCAE);
+        builder.AddItem(195, 90, 0xCAD);
+        builder.AddItem(218, 95, 0xCB0);
+
+        builder.AddHtml(30, 30, 150, 75, "<div align=center>Wilt thou sanctify the resurrection of:</div>");
+        builder.AddHtmlPlaceholder(30, 70, 150, 25, "petName", true);
+
+        builder.AddButton(40, 105, 0x81A, 0x81B, 0x1);  // Okay
+        builder.AddButton(110, 105, 0x819, 0x818, 0x2); // Cancel
+    }
+
+    protected override void BuildStrings(ref GumpStringsBuilder builder)
+    {
+        builder.SetStringSlot("petName", $"<CENTER>{_petName}</CENTER>");
+    }
+}