fix: Moves ContextMenu out of core, streamlines code, fixes bugs (#1873)

## Summary
- Removes allocation of a `List<ContextMenuEntry>` every time a context menu is created.
- Moves packet/context menu creation logic out of the core
- Fixes tame entry

## BREAKING CHANGE
> [!Important]
> **Developer Note**
> ```cs
> public virtual void GetContextMenuEntries(Mobile from, List<ContextMenuEntry> list)
> ```
> and similar functions changed to
> ```cs
> public virtual void GetContextMenuEntries(Mobile from, ref PooledRefList<ContextMenuEntry> list)
> ```

Projects/UOContent/Context Menus/AddToSpellbookEntry.cs

@@ -9,11 +9,11 @@ namespace Server.ContextMenus
         {
         }
 
-        public override void OnClick()
+        public override void OnClick(Mobile from, IEntity target)
         {
-            if (Owner.From.CheckAlive() && Owner.Target is SpellScroll scroll)
+            if (from.CheckAlive() && target is SpellScroll scroll)
             {
-                Owner.From.Target = new InternalTarget(scroll);
+                from.Target = new InternalTarget(scroll);
             }
         }