s3/utils: Add functionality to smbcacls to save dacl(s) to a restore file

s3/utils: Add functionality to smbcacls to save dacl(s) to a restore file

Add similar functionality to 'icacls name /save'

Save dacls for a file/directory to a restore/save file.
When saving dacls associated with a directory, using the 'recusive'
switch '-T' will recursively save the content of the directory.

Note: the save file produced by smbcacls and icacls are interchangeable
      as smbcacls produces (and uses) the same file format.

Signed-off-by: Noel Power <noel.power@suse.com>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>