Explicitly set the WAN MAC address on all models where WAN is a VLAN device

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.
Add new package gluon-wan-dnsmasq

This package provides a secondary dnsmasq instance on port 54 which resolves
everything over the WAN interface.
gluon-mesh-vpn-fastd: use gluon-wan-dnsmasq
gluon-core: remove now unused dnsmasq.d support
gluon-luci-theme: remove top padding cbi-field-title

This allows to use cbi-field to format plain text instead of form fields.
gluon-luci-admin: add an info page
gluon-core: add unique node_id

This adds a `node_id` to announce.d. `node_id` is an hex-number uniquely
identifying a particular node. On nodes having a
primary MAC this MAC address will be used as `node_id` (sans the
colons). The value is opaque. It must not be converted back into
a MAC address.

`node_id` should be sent in all alfred and announced packets to
ensure clients can link the data to a particular node.
split announce.d into nodeinfo + statistics