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/Base/Grid/Grid.cs

@@ -0,0 +1,77 @@
+/*************************************************************************
+ * ModernUO                                                              *
+ * Copyright 2019-2023 - ModernUO Development Team                       *
+ * Email: hi@modernuo.com                                                *
+ * File: Grid.cs                                                         *
+ *                                                                       *
+ * This program is free software: you can redistribute it and/or modify  *
+ * it under the terms of the GNU General Public License as published by  *
+ * the Free Software Foundation, either version 3 of the License, or     *
+ * (at your option) any later version.                                   *
+ *                                                                       *
+ * You should have received a copy of the GNU General Public License     *
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
+ *************************************************************************/
+
+using System.Collections.Generic;
+
+namespace Server.Gumps;
+
+public enum GridHues
+{
+    White = 2049, // Change to 0x480 if you have old hues.mul
+    Black = 0,
+}
+
+public static class GridColors
+{
+    public const string Gold = "#ffc959";
+    public const string White = "#ffffff";
+    public const string Blue = "#1D63DC";
+    public const string LightBlue = "#7799EE";
+    public const string Green = "#80E732";
+    public const string Orange = "#F28B00";
+    public const string Purple = "#F3ACF6";
+    public const string Red = "#B52B2D";
+    public const string LightGreen = "#E6FFC0";
+    public const string Yellow = "#FFFFBB";
+}
+
+public class ListItem
+{
+    public int X { get; set; }
+    public int Y { get; set; }
+    public int Index { get; set; }
+    public Col[] Cols { get; set; }
+}
+
+public class Col
+{
+    public int X { get; set; }
+    public int Width { get; set; }
+    public int HCenter => X + Width / 2;
+    public int HEnd => X + Width;
+}
+
+public class Row
+{
+    public int Y { get; set; }
+    public int Height { get; set; }
+    public int VCenter => Y + Height / 2;
+    public int VEnd => Y + Height;
+}
+
+public class Grid
+{
+    public string Name { get; set; }
+    public int Height { get; set; }
+    public int Width { get; set; }
+    public List<Col> Columns { get; set; } = new();
+    public List<Row> Rows { get; set; } = new();
+}
+
+public class Swap
+{
+    public int Index { get; set; }
+    public int Size { get; set; }
+}