s3:smbd: add SMB2 AAPL create context defines and options

Add a global SMB2 specific option 'use_aapl_crtctx'. It's off by
default, but later enabled in the vfs_fruit module.

Add a AAPL specific capability flag 'smb2_crtctx_aapl_readdir_attr',
when used several fields in an SMB2/FIND reply are repurposed
returning Mac specific file attributes including resource fork length,
unix mode and max_access.

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>
libcli/security: add NFS SID mappings

Signed-off-by: Ralph Boehme <rb@sernet.de>
vfs_fruit: check option "smb2 create tag:aapl"

The default for the option is true, which means we support Apple's
AAPL SMB2 create context stuff.

Signed-off-by: Ralph Boehme <rb@sernet.de>
s3:smbd: SMB2 AAPL create context: SMB2/FIND extension

smb2_crtctx_aapl_readdir_attr = true | false

If enabled, several fields in an SMB2/FIND reply are repurposed
returning Mac specific file attributes including resource fork
length, UNIX mode, FinderInfo and max_access.

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>