This will introduce a new nodeinfo object, network.mesh.bat0.interfaces,
containing any of the the following subordinated objects:

- wireless
- tunnel
- other

Each of these objects contains a (possibly empty) list of MAC addresses
(lowercase, colon-notation) corresponding to a interface of the given
class. Combined with a batman graph it is thus possible to mark
sub-graphs as "wireless" or "vpn".

The previously used object mesh_intefaces is superseded by this new
object structure and mesh_interfaces will be removed in a future Gluon
release.

This will require site.mk to explicitly pull in the gluon-setup-mode and
gluon-config-mode-core packages.

This also adds an extended query protocol and deflate compression.

Having two POT files will only cause confusion.

In Bremen it has been noted that a prefix may lead people to believe it
has to stay there and thus naming their nodes "ffhb-*", which is not
what the community wants (see FreifunkBremen/gluon-site-ffhb#1).

However, an empty prefix lead to the connecting hyphen still being
inserted. This commit thus makes the hyphen part of the configured
prefix and allows the prefix to be missing from the `site.conf`.

Fixes https://github.com/freifunk-gluon/gluon/issues/311

This avoids poking dnsmasq every time a DHCP lease is obtained or a router
advertisement received.

This adds basic peer statistics to statistics.d:

    "mesh_vpn": {
      "muehlentor": {
        "established": 23.8 // seconds
      },
      "huextertor": null,
      "holstentor": null
    }