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/BaseGump.cs

@@ -0,0 +1,89 @@
+/*************************************************************************
+ * ModernUO                                                              *
+ * Copyright 2019-2024 - ModernUO Development Team                       *
+ * Email: hi@modernuo.com                                                *
+ * File: BaseGump.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 Server.Network;
+using System;
+using System.Buffers;
+using System.Runtime.CompilerServices;
+
+namespace Server.Gumps;
+
+public abstract class BaseGump
+{
+    private static readonly byte[] _packetBuffer = GC.AllocateUninitializedArray<byte>(0x10000);
+    private static Serial nextSerial = (Serial)1;
+
+    public int TypeID { get; protected set; }
+    public Serial Serial { get; protected set; }
+
+    public abstract int Switches { get; }
+    public abstract int TextEntries { get; }
+
+    public int X { get; set; }
+    public int Y { get; set; }
+
+    /**
+     * If true, only one instance of this gump can be open at a time per player.
+     */
+    public virtual bool Singleton => false;
+
+    public BaseGump(int x, int y) : this()
+    {
+        X = x;
+        Y = y;
+    }
+
+    public BaseGump()
+    {
+        Serial = nextSerial++;
+        TypeID = GetTypeId(GetType());
+    }
+
+    public virtual void SendTo(NetState ns)
+    {
+        var writer = new SpanWriter(_packetBuffer);
+        Compile(ref writer);
+
+        ns.Send(writer.Span);
+
+        writer.Dispose();
+    }
+
+    public abstract void Compile(ref SpanWriter writer);
+
+    public virtual void OnResponse(NetState sender, in RelayInfo info)
+    {
+    }
+
+    public virtual void OnServerClose(NetState owner)
+    {
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static int GetTypeId(Type type)
+    {
+        unchecked
+        {
+            // To use the original .NET Framework deterministic hash code (with really terrible performance)
+            // change the next line to use HashUtility.GetNetFrameworkHashCode
+            var hash = (int)HashUtility.ComputeHash32(type?.FullName);
+
+            const int primeMulti = 0x108B76F1;
+
+            // Virtue Gump
+            return hash == 461 ? hash * primeMulti : hash;
+        }
+    }
+}