Added modifications as suggested from my initial pull request
Added modifications as suggested from my initial pull request

Added more verbose WhatIf processing for files
Changed RetentionTime to a required parameter
Added verbose HelpMessage for all required parameters
wsmelton/dbatools,SirCaptainMitch/dbatools,sqlpadawan/dbatools,alevyinroc/dbatools,Splaxi/dbatools,dsolodow/dbatools,kozloski/dbatools