fix(Core/Grid): Address bugs and performance issues introduced by visibility notifier implementation (#17480)

* Bug fixes

- Corrected std::chrono from seconds to milliseconds
- Got rid of leftover code that caused objects to not show up on time

* Removed logic to set gameobject as active

- More alignement with TC.
- Reduces CPU usage drastically

* Revert back to using time_t instead of std chrono

* Invoke SetNoCreate() method to reduce CPU usage drastically

* Remove setActive from static and motion transports

* Fix performance issues

* Added SetFarVisible to WG and some dungeon scripts

- Also removed setActive(true) from creatures in Wintergrasp. As for gameobjects they are set to active upon being damaged/destroyed and removed from active on rebuild (reset)

* Removed comments related to VISIBILITY_COMPENSATION

* Fix log

* Deleted unused files + corrected a check

* Added missing header

* Removed unused parameter

* Removed another unsued parameter

* Changed vector to set for i_visibleNow

- Changed vector to set for i_visibleNow in VisibleNotifer
- Adjusted HaveAtClient to accept Object*
- Adjusted SendUpdateToPlayer to send createobject packet only if not known to client

src/server/game/Maps/MapInstanced.cpp

@@ -25,8 +25,9 @@
 #include "Player.h"
 #include "ScriptMgr.h"
 #include "VMapFactory.h"
+#include "VMapMgr2.h"
 
-MapInstanced::MapInstanced(uint32 id, std::chrono::seconds expiry) : Map(id, expiry, 0, DUNGEON_DIFFICULTY_NORMAL)
+MapInstanced::MapInstanced(uint32 id, time_t expiry) : Map(id, expiry, 0, DUNGEON_DIFFICULTY_NORMAL)
 {
     // fill with zero
     memset(&GridMapReference, 0, MAX_NUMBER_OF_GRIDS * MAX_NUMBER_OF_GRIDS * sizeof(uint16));
@@ -260,6 +261,15 @@ bool MapInstanced::DestroyInstance(InstancedMaps::iterator& itr)
     sScriptMgr->OnDestroyInstance(this, itr->second);
 
     itr->second->UnloadAll();
+    // should only unload VMaps if this is the last instance
+    if (m_InstancedMaps.size() <= 1)
+    {
+        VMAP::VMapFactory::createOrGetVMapMgr()->unloadMap(itr->second->GetId());
+        MMAP::MMapFactory::createOrGetMMapMgr()->unloadMap(itr->second->GetId());
+        // in that case, unload grids of the base map, too
+        // so in the next map creation, (EnsureGridCreated actually) VMaps will be reloaded
+        Map::UnloadAll();
+    }
 
     // erase map
     delete itr->second;