Some tests and tweaks
Some tests and tweaks

- Removed Copy-Item method (is synchronous).
- If robocopy exists will use it instead of Start-BitsTransfer. Robocopy
is much faster. (1GB  -> Down from 23sec to 6sec)
- MD5 generation can be (1GB +- 13sec)

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