The field was accidentally removed during the status-page rewrite.

Fixes #1401

batman-adv-specific parts are moved to a new package
gluon-status-page-mesh-batman-adv.

gluon-status-page: reduce usage of absolute paths in cgi-bin scripts neighbours-nodeinfo and stations

Some HTTP endpoints were writing annoying "broken pipe" messages to stderr.

A downside of this behaviour is that the page does not work for IPv4-only
clients, as the redirect will always point at an IPv6 address.

Still, it seems like a good idea to enforce the redirect even from the IPv4
next-node address, as switching nodes while being connected to the status
page would lead to unexpected behaviour.

All Access-Control-Allow-Origin are removed to improve users' privacy. As
the status page API is thus not useful without the status page anymore,
merge them back into a single package.

The status-page-api respondd provider is removed as well.

Fixes #1194

This new status page is significantly smaller than the old one. It always
loads its resources from the same host as the page itself, not requiring
cross-origin requests anymore.

It also uses the common i18n infrastructure of gluon-web.

Fixes #914

We have Git for history, there's no reason to keep old files that aren't
used anymore.

This will make it easier to replace the API with C programs.

Apart from replacing a patch for the former by two patches for latter,
this involved minimal adaptations of the lua scripts in the following
packages:

* gluon-announce
* gluon-announced
* gluon-mesh-batman-adv-core
* gluon-status-page

This limits the number of concurrent users to 2 or 3 (approx. 4 connections per
user), greatly reducing DoS potential.

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The previously used object mesh_intefaces is superseded by this new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.

Moving the scripts to a common directory not only vastly simplifies the
zzz-gluon-upgrade script, but also allows to define an ordering of such
scripts across packages.

The whole status page should be rewritten ASAP, but this fix will at least
make it work again for now...