From and after the expiration of the terms of office of present municipal officers, the mayor and board of aldermen of all municipalities operating under this chapter shall have the power and authority to appoint a street commissioner, and such other officers and employees as may be necessary, and to prescribe the duties and fix the compensation of all such officers and employees. All officers and employees so appointed shall hold office at the pleasure of the governing authorities and may be discharged by such governing authorities at any time, either with or without cause. The governing authorities of municipalities shall have the power and authority, in their discretion, to appoint the same person to any two (2) or more of the appointive offices, and in a municipality having a population of less than fifteen thousand (15,000), according to the latest available federal census, a member of the board of aldermen may be appointed to the office of street commissioner. In municipalities not having depositories, the clerk shall serve as ex officio treasurer. The municipal governing authorities shall require all officers and employees handling or having the custody of any public funds of such city to give bond, with sufficient surety, to be payable, conditioned and approved as provided by law, in an amount to be determined by the governing authority (which shall be not less than Fifty Thousand Dollars ($50,000.00)), the premium on same to be paid from the municipal treasury. The terms of office or employment of all officers and employees so appointed shall expire at the expiration of the term of office of the governing authorities making the appointment, unless such officers or employees shall have been sooner discharged as herein provided. All officers and employees so appointed are authorized to serve until the appointment and qualification of their successors not exceeding the limitation period provided in Section 21-15-41.