It is the intent of this chapter to confirm expressly the authority of counties to grant franchises for, and to regulate by ordinance or resolution, cable television systems within their territorial limits, except as limited by Code Section 36-18-3. Nothing in this chapter shall be construed to impair any cable television system franchise license lawfully issued by a county or municipality prior to April 9, 1981; and any such license shall be entitled to the benefits of this chapter.