This will make a node announce all MACs of its interfaces participating
in the batman-adv mesh. This enables other nodes to associate the
announced object with both the data reported by batadv-vis as well as a
simple list of neighbours as output by `iw dev $IFACE station dump`.

All announce.d scripts have been moved to /lib/gluon/announce/announce.d
The script /lib/gluon/announce/announce.lua will collect all information
and output json.