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/Engines/Veteran Rewards/Character Statue Maker/CharacterStatue.cs

@@ -591,8 +591,7 @@ public class CharacterStatueTarget : Target
             _maker.Delete();
             statue.Sculpt(from);
 
-            from.CloseGump<CharacterStatueGump>();
-            from.SendGump(new CharacterStatueGump(_maker, statue, from));
+            from.SendGump(new CharacterStatueGump(_maker, statue, from), true);
             return;
         }
 

Projects/UOContent/Engines/Veteran Rewards/RewardChoiceGump.cs

@@ -8,12 +8,12 @@ namespace Server.Engines.VeteranRewards
     {
         private readonly Mobile m_From;
 
+        public override bool Singleton => true;
+
         public RewardChoiceGump(Mobile from) : base(0, 0)
         {
             m_From = from;
 
-            from.CloseGump<RewardChoiceGump>();
-
             RenderBackground();
             RenderCategories();
         }

Projects/UOContent/Engines/Veteran Rewards/RewardConfirmGump.cs

@@ -9,13 +9,13 @@ namespace Server.Engines.VeteranRewards
         private readonly RewardEntry m_Entry;
         private readonly Mobile m_From;
 
+        public override bool Singleton => true;
+
         public RewardConfirmGump(Mobile from, RewardEntry entry) : base(0, 0)
         {
             m_From = from;
             m_Entry = entry;
 
-            from.CloseGump<RewardConfirmGump>();
-
             AddPage(0);
 
             AddBackground(10, 10, 500, 300, 2600);

Projects/UOContent/Engines/Veteran Rewards/RewardDemolitionGump.cs

@@ -8,6 +8,8 @@ namespace Server.Gumps
     {
         private readonly IAddon m_Addon;
 
+        public override bool Singleton => true;
+
         public RewardDemolitionGump(IAddon addon, int question) : base(150, 50)
         {
             m_Addon = addon;

Projects/UOContent/Engines/Veteran Rewards/RewardNoticeGump.cs

@@ -7,12 +7,12 @@ namespace Server.Engines.VeteranRewards
     {
         private readonly Mobile m_From;
 
+        public override bool Singleton => true;
+
         public RewardNoticeGump(Mobile from) : base(0, 0)
         {
             m_From = from;
 
-            from.CloseGump<RewardNoticeGump>();
-
             AddPage(0);
 
             AddBackground(10, 10, 500, 135, 2600);

Projects/UOContent/Engines/Veteran Rewards/RewardOptionGump.cs

@@ -14,6 +14,8 @@ namespace Server.Gumps
         private readonly IRewardOption m_Option;
         private readonly RewardOptionList m_Options = new();
 
+        public override bool Singleton => true;
+
         public RewardOptionGump(IRewardOption option, int title = 0) : base(60, 36)
         {
             m_Option = option;

Projects/UOContent/Engines/Veteran Rewards/RewardSystem.cs

@@ -1,5 +1,6 @@
 using System;
 using Server.Accounting;
+using Server.Gumps;
 using Server.Items;
 using Server.Mobiles;