Also move it to gluon-mesh-batman-adv, as mesh_on_wan is the only feature that
needs a unique MAC address on the WAN interface.

The now empty gluon-firewall is removed.

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.

This also fixes the type of a few fields which were strings instead of numbers.

For security reasons we should not accept incoming packets per default
and instead allow specific services on specific interfaces.

gluon-mesh-batman-adv should not be used without firewall to prevent forwarding
of packets from the mesh to the wan interface.

For some reason, the firewall package won't work at all without
kmod-ipt-nathelper.

Disabling forwarding prevents the node from reacting to the Subnet-Router
anycast address.