The people of the City reserve the power of direct legislation by initiative, and in the exercise of such power may propose any ordinance, except zoning ordinances and ordinances appropriating money or levying taxes, or ordinances repealing zoning ordinances and ordinances appropriating money or levying taxes, not in conflict with this Charter or the Constitution or Laws of the State of Texas. Any initiated ordinance may be submitted to the City Council by a petition signed by the qualified voters of the City equal in number to at least twenty percent (20%) of the qualified voters of the City.