dsdb: Move anonymous domain_data struct

dsdb: Move anonymous domain_data struct

Anonymous structs and 80 character line-lengths don't mix well. Allow
the struct to be referenced directly.

With the introduction of PSOs, the password-settings are now calculated
per-user rather than per-domain. I've tried to reflect this in the
struct name.

Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>