All official action of the council shall be by ordinance or resolution adopted by the affirmative vote of not less than a quorum of the council, unless otherwise required by law or this charter. All actions of the council which do not constitute ordinances shall be deemed to be resolutions. Action by resolution shall be limited to matters required or permitted to be so done by law or pertaining to the internal affairs or concerns of the city government. All other acts of the council and all acts carrying a penalty for the violation thereof, shall be by ordinance. Each ordinance shall be identified by a short title and by a number.