Core/Players: Use CharBaseInfo.db2 data to determine appropriate race for mercenary mode transforms

Port From (https://github.com/TrinityCore/TrinityCore/commit/c2ac37125b566cb4d9b659bc8ae2d381f60bc6db)

Source/Game/DataStorage/Structs/C_Records.cs

@@ -43,6 +43,14 @@ namespace Game.DataStorage
         public uint SrcItemBonusTreeID;
     }
 
+    public sealed class CharBaseInfoRecord
+    {
+        public uint Id;
+        public sbyte RaceID;
+        public sbyte ClassID;
+        public int OtherFactionRaceID;
+    }
+
     public sealed class CharTitlesRecord
     {
         public uint Id;