[Quest API] Add GetEXPForLevel() to Perl/Lua (#3403)

# Perl
- Add `$client->GetEXPForLevel(check_level)`.

# Lua
- Add `client:GetEXPForLevel(check_level)`.

# Notes
- This allows operators to see the required experience for a level based on the client provided, this takes race/class modifiers into account as well if enabled.

zone/client.h

@@ -1641,6 +1641,7 @@ public:
 	PlayerEvent::PlayerEvent GetPlayerEvent();
 	void RecordKilledNPCEvent(NPC *n);
 
+	uint32 GetEXPForLevel(uint16 check_level);
 protected:
 	friend class Mob;
 	void CalcEdibleBonuses(StatBonuses* newbon);
@@ -1816,7 +1817,6 @@ private:
 	bool temp_pvp;
 
 	void NPCSpawn(const Seperator* sep);
-	uint32 GetEXPForLevel(uint16 level);
 
 	void SendLogoutPackets();
 	void SendZoneInPackets();