Section 5. Self-government charters. (1) The legislature shall provide procedures permitting a local government unit or combination of units to frame, adopt, amend, revise, or abandon a self-government charter with the approval of a majority of those voting on the question. The procedures shall not require approval of a charter by a legislative body.
     (2) If the legislature does not provide such procedures by July 1, 1975, they may be established by election either:
     (a) Initiated by petition in the local government unit or combination of units; or
     (b) Called by the governing body of the local government unit or combination of units.
     (3) Charter provisions establishing executive, legislative, and administrative structure and organization are superior to statutory provisions.