s3:net ads dns register: add support for specifying addresse on the commandline ...

s3:net ads dns register: add support for specifying addresse on the commandline (bug #7871)

In the clustering case, this is also made the only possiblity to do dns updates,
since the list addresses on the local interfaces is not suitable in that case.

This fixes the "net ads dns register" part of bug #7871.
It might be extended by a parsing of the "cluster addresses" setting.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
(cherry picked from commit 5e83a05009787d8a2086db1adc1ed58d61b3725d)
(cherry picked from commit 9ed3d33fb3d7365a127ea2752032840272697902)