Any municipal corporation which adopts the council-manager form of government shall continue its existence as a body corporate without change in the municipal corporation. The word “municipality” as herein used shall mean and refer to any municipal corporation which has adopted the council-manager form of government. The city shall continue as a municipal corporation, within the corporate limits as then established, and as thereafter fixed in the manner prescribed by law, subject to all the duties and obligations then pertaining to or incumbent upon it as a municipal corporation and shall continue to enjoy the rights, immunities, powers, and franchises then enjoyed by it, as well as those that may thereafter be granted to it.