[Code] LoginServerList Global to Singleton Cleanup (#4941)

world/login_server_list.h

@@ -21,6 +21,13 @@ public:
 	bool	SendAccountUpdate(ServerPacket *pack);
 	bool	Connected();
 	size_t GetServerCount() const { return m_list.size(); }
+
+	static LoginServerList* Instance()
+	{
+		static LoginServerList instance;
+		return &instance;
+	}
+
 protected:
 	std::list<std::unique_ptr<LoginServer>> m_list;
 };