refactor(Core/Entities): Cleanup Unit header file (#19622)

* move several enum definitions in a new files

* move more things

* remove the include comment

* move the related code to CharmInfo in this own file

*original idea of Ovahlord

Co-Authored-By: Ovahlord <18347559+Ovahlord@users.noreply.github.com>

* fix clang build errors and few blank lines

* missing forward declaration

* new tentative to fix gcc/clang build

* add several include could be necessary for gcc/clang compilation

* .

* revert some include since the last AC update

* fix some loop inconsistencies

* align all enums in UnitDefine.h

---------

Co-authored-by: Ovahlord <18347559+Ovahlord@users.noreply.github.com>

src/server/game/Entities/Vehicle/Vehicle.h

@@ -96,4 +96,15 @@ private:
     Status _status;
 };
 
+class VehicleDespawnEvent : public BasicEvent
+{
+public:
+    VehicleDespawnEvent(Unit& self, uint32 duration) : _self(self), _duration(duration) { }
+    bool Execute(uint64 e_time, uint32 p_time) override;
+
+protected:
+    Unit& _self;
+    uint32 _duration;
+};
+
 #endif