The department of law shall be headed by a director of law, who shall be an attorney admitted to practice law in the state, shall be a registered voter of the city, and shall be appointed by the mayor with the approval of council. The director of law shall serve as chief legal adviser to council, the mayor, all boards and commissions, and all city departments, offices and agencies; shall represent the city in all legal proceedings; and shall perform any other duties prescribed by this charter, ordinance, resolution or general law, except as general law may be limited by council.