This change will split common folder to four different folders:
Linux, Unix, Windows and MacOS. Each of these folders includes scripts
which are common for their operating system familes
Task-number: QTQAINFRA-1451
Change-Id: I0668885da43222663a54521ce85653da697425be
Reviewed-by: Heikki Halmet <heikki.halmet@qt.io>