naywatch: add naywatch

naywatch: add naywatch

The network may crash on the SoCs, but the SoC itself does not. This
leads to a node no longer being accessible in a mesh network.  If the
node is placed in a location that is not easily accessible, e.g. in a
high tower, it can cause a lot of problems. Therefore we check the
link-local connectivity on the configured interfaces.

Signed-off-by: Nick Hainke <vincent@systemli.org>
Tested-by: Simon Polack <spolack+git@mailbox.org>
Signed-off-by: Simon Polack <spolack+git@mailbox.org>
(cherry picked from commit 1088e65440b1f2f67b40e6a3073571da14f6a4b3)