Add SYSTEM_SECURITY access flag and use with smb2 when opening
files for getting/setting SACLs. Add "system.cifs_ntsd_full"
extended attribute to allow user-space access to the functionality.
Avoid multiple server calls when setting owner, DACL, and SACL.
Signed-off-by: NBoris Protopopov <pboris@amazon.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>