feat(Core/Maps): Implement dynamic respawn rates (#21417)

Co-authored-by: r00ty-tc <r00ty-tc@users.noreply.github.com>
Co-authored-by: Jelle Meeus <sogladev@gmail.com>
Co-authored-by Treeston

This is a partial cherry-pick of: https://github.com/TrinityCore/TrinityCore/pull/19056/commits/59db2eeea0a35028779fd76372ae06cc98c8086f

src/server/game/Maps/Map.h

@@ -594,6 +594,9 @@ public:
     void DeleteRespawnTimes();
     [[nodiscard]] time_t GetInstanceResetPeriod() const { return _instanceResetPeriod; }
 
+    void UpdatePlayerZoneStats(uint32 oldZone, uint32 newZone);
+    void ApplyDynamicModeRespawnScaling(WorldObject const* obj, uint32& respawnDelay) const;
+
     TaskScheduler _creatureRespawnScheduler;
 
     void ScheduleCreatureRespawn(ObjectGuid /*creatureGuid*/, Milliseconds /*respawnTimer*/, Position pos = Position());
@@ -780,6 +783,8 @@ private:
     std::unordered_map<ObjectGuid::LowType /*dbGUID*/, time_t> _creatureRespawnTimes;
     std::unordered_map<ObjectGuid::LowType /*dbGUID*/, time_t> _goRespawnTimes;
 
+    std::unordered_map<uint32, uint32> _zonePlayerCountMap;
+
     ZoneDynamicInfoMap _zoneDynamicInfo;
     uint32 _defaultLight;