Enhancement: Back up and restore SecurityDescriptors on Windows

Restic now backs up and restores SecurityDescriptors when backing up files and folders 
on Windows which includes owner, group, discretionary access control list (DACL), 
system access control list (SACL). This requires the user to be a member of backup 
operators or the application must be run as admin.
If that is not the case, only the current user's owner, group and DACL will be backed up 
and during restore only the DACL of the backed file will be restored while the current 
user's owner and group will be set during the restore.

https://github.com/restic/restic/pull/4708