Replace Join-Path with System.IO.Path::Combine
Replace Join-Path with System.IO.Path::Combine

- Join-Path test the existing to drive we use. When accessing UNC paths
I can access to drive letters that I don't have on my PC (where I'm
running the scrip).

- Added /COP:DATS parameter to robocopy in order to keep file
permissions.

dsolodow/dbatools,Splaxi/dbatools,alevyinroc/dbatools,SirCaptainMitch/dbatools,kozloski/dbatools,sqlpadawan/dbatools,wsmelton/dbatools