It is hereby declared as a matter of legislative determination that (a) in order to promote and protect the health, safety, morals and welfare of the public, it is necessary in the public interest to provide for the creation of public corporate bodies to be known as housing authorities and to confer upon and vest in such housing authorities all powers necessary or appropriate in order that they may engage in low-cost housing and slum clearance projects and (b) the powers herein conferred upon the housing authorities, including the power to acquire property, to remove unsanitary or substandard conditions, to construct and operate housing accommodations and to borrow, expend, lend and repay moneys for the purposes herein set forth, are public objects essential to the public interest.