It is the purpose of the Local Government Securities Law to provide a procedure for financing any projects otherwise authorized by law (other than by the levy and collection of special assessments) and for the issuance of securities to evidence or reevidence obligations incurred in connection with any such projects. The Local Government Securities Law is supplemental in nature, and nothing herein contained shall be construed as authorizing any particular project nor as authorizing the incurrence of any obligations to defray the cost of any project.