s3:smbd: flags for NFS ACE in AAPL create context

Add define and flag for NFS ACE in AAPL create context. With this
extension, a client can use get_info(sec)/set_info(sec) for

- retrieving UNIX uid,gid and mode of a file with get_info
- modifying UNIX mode with set_info

Signed-off-by: Ralph Boehme <rb@sernet.de>
squash: aapl acl stuff

Signed-off-by: Ralph Boehme <rb@sernet.de>
libcli/security: add NFS SID mappings

Signed-off-by: Ralph Boehme <rb@sernet.de>
vfs_fruit: SMB2 AAPL create_context: NFS ACEs

Return uid, gid and mode in NFS ACEs append them to the ACL we get
from the next VFS module.

Extract mode from client NFS ACE and apply it.

Signed-off-by: Ralph Boehme <rb@sernet.de>