Any town may make reasonable ordinances with reference to the licensing of junk dealers engaged in business therein, including the imposition of a license fee in an amount to be fixed by the selectmen at a sum not less than two dollars or more than ten dollars a year, for each team or vehicle used in connection with such business, for the privilege of carrying on such business. Each such junk dealer shall make an application for a license in the town where such dealer is engaged in business. Nothing in this section shall prohibit a junk dealer or employee of such dealer from authorizing a person to enter a junk yard owned by such dealer for the purpose of salvaging or collecting parts or scraps for purchase from such dealer or employee. Except as otherwise provided by special act, and except where there exists a duly constituted local zoning or planning commission, any town, city or borough may, by ordinance, regulate the establishment, location or conduct of any junk yard within its territorial limits.