Fixes #534

Fixes #487

gluon-mesh-batman-adv-core/gluon-luci-portconfig: fix configuration of br-client ifname with multiple interfaces in lan_ifname

There are a few devices on which lan_ifname contains multiple interface
names separated by spaces.

This package provides br-client and sets up a wireless AP interface for
clients.

gluon-radio-config contained only a single file. The code has been adjusted
to allow creating a Gluon configuration without WLAN support by removing
the wifi24 and wifi5 sections from site.conf.

gluon-mesh-batman-adv-core: neighbours.d/wifi: output empty object instead of empty list when there are no neighbours on an interface

The Gluon-specific functions of the gluon-simple-tc package are moved to
gluon-mesh-vpn-fastd.

The file promotes the probably unnecessary re-execution of the announce
scripts. Instead, gluon-announced should be queried using

    gluon-neighbour-info -d ::1 -p 1001 -t0 -r nodeinfo

if both gluon-announced and gluon-neighbour-info are present. But to not
depend on any of those, no script for this one-liner is provided.

By not executing all scripts from gluon.announce themselves, both should
be considerably faster and lighter on RAM usage.

The new options allow specifying custom repositories and are evaluated
in an upgrade script, not during build.

Fixes #401

By calling collectgarbage() at various places I was able to reduce heap
usage by ~270kb.

collect_dir() will now pre-load all files and return a function that will
collect all information.

The expert mode can still be useful without any cohfig mode modules.

keep macfilter and maclist config after fw-update

additional information for commit 2a93c580

Now that the status page api has been rewritten in C CPU load and memory
usage is much lower. Also, nodes with both ibss and 11s mesh and dual
band wifi may require up to 9 connections for a single client, thus the
previous limit of 12 seemed a little low.

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

Convert option ifname in br-client to use a list instead. This
simplifies adding and remove interfaces:

uci:add_to_set("network", "client", "ifname", "eth0")
uci:remove_from_set("network", "client", "ifname", "eth0")

An option ifname will be automatically converted to a list when
performing an upgrade.

Packages affected: gluon-mesh-batman-adv-core, gluon-luci-portconfig

When rebooting the node in config mode, currently the fastd key is
forcefully displayed in a fixed format. This is confusing in communities
where fastd accepts all keys and no key submission is needed.
Furthermore, some communities might want to personalize the display of
the key (see #387).

This patch moves the displaying <div> from the package's lua file to the
translation files of the sample site configuration and mentiones the
change in the release notes.

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

Split basic radio configuration from gluon-mesh-batman-adv as this will
be required for virtually any wireless mesh protocol.

This package takes care of setting:

  - wireless channel,
  - htmode and
  - regulatory domain

gluon-mesh-batman-adv-core depends on this package.