A city may, except as expressly limited by the Constitution of the State of Iowa, and if not inconsistent with the laws of the general assembly, exercise any power and perform any function it deems appropriate to protect and preserve the rights, privileges, and property of the city or of its residents, and to preserve and improve the peace, safety, health, welfare, comfort, and convenience of its residents. This grant of home rule powers does not include the power to enact private or civil law governing civil relationships, except as incident to an exercise of an independent city power.