Sections 32-23d to 32-23k, inclusive, shall be deemed to provide a complete method for the doing of the things authorized thereby and shall be regarded as not in conflict with, or as restrictive of, powers conferred by any other laws, any other existing provisions of the general statutes notwithstanding. No proceedings, notice or approval shall be required for the issuance of any bonds or notes or any instrument as security therefor, except as is herein provided.