Core/Objects: Unify Searcher classes into one common implementation

Port From (https://github.com/TrinityCore/TrinityCore/commit/261eb201bf107cef441d9b075e8f23bf0edfbaf0)
Port From (https://github.com/TrinityCore/TrinityCore/commit/526b16fea41fb69a302fdebe8a727e175949f04b)
Port From (https://github.com/TrinityCore/TrinityCore/commit/8b7dce6521323e788ebf28297ec941a6f9bf876f)
Port From (https://github.com/TrinityCore/TrinityCore/commit/5334467f493eb16141f4ad0bce956bc3e19244a0)
Port From (https://github.com/TrinityCore/TrinityCore/commit/1e7725c15b149baaf96731231239769e482ec2ed)
Port From (https://github.com/TrinityCore/TrinityCore/commit/21712f475383f6f3fae107706f5de5195f75b760)

Source/Game/Chat/Commands/DebugCommands.cs

@@ -142,7 +142,7 @@ namespace Game.Chat
                 var check = new AllCreaturesOfEntryInRange(handler.GetPlayer(), entry, 20.0f);
                 var searcher = new CreatureSearcher(handler.GetPlayer(), check);
                 Cell.VisitAllObjects(handler.GetPlayer(), searcher, 30.0f);
-                var passenger = searcher.GetTarget();
+                var passenger = searcher.GetResult();
                 if (passenger == null || passenger == target)
                     return false;
                 passenger.EnterVehicle(target, seatId);

Source/Game/Chat/Commands/MiscCommands.cs

@@ -1571,7 +1571,8 @@ namespace Game.Chat
             }
 
             // First handle any creatures that still have a corpse around
-            var worker = new WorldObjectWorker(player, new RespawnDo());
+            RespawnDo u_do = new();
+            WorldObjectWorker<Creature> worker = new(player, u_do);
             Cell.VisitGridObjects(player, worker, player.GetGridActivationRange());
 
             // Now handle any that had despawned, but had respawn time logged.