ns: Track services per node
ns: Track services per node

In order to easily shoot down all services when a remote node goes away,
or list all local services when announcing inject a "node" layer above
the services map.

Signed-off-by: Bjorn Andersson <6e6fda072d932515099508d6d220572c68e9add5@linaro.org>

andersson/qrtr,andersson/qrtr,andersson/qrtr