The Secretary of Housing and Urban Development may appoint such officers and employees as he may find necessary, which appointments shall be subject to the civil-service laws and chapter
51 and subchapter
III of chapter
53 of title
5. The Secretary may make such expenditures as may be necessary to carry out his functions, powers, and duties, and there are authorized to be appropriated to the Secretary, out of any moneys in the Treasury not otherwise appropriated, such sums as may be necessary to carry out such functions, powers, and duties and for administrative expenses in connection therewith. The Secretary, without in any way relieving himself from final responsibility, may delegate any of his functions and powers to such officers, agents, or employees as he may designate, may authorize such successive redelegations of such functions and powers, as he may deem desirable, and may make such rules and regulations as may be necessary to carry out his functions, powers, and duties.