The upstream builds always use LINUX_RELEASE=1. By setting it to 2 we
ensure that our modules are always preferred as long as our kernel version
is at least as high as the upstream one.

As the Gluon kernel won't be compatible with the OpenWrt upstream anymore,
we don't need the vermagic hack anymore.

doc: remove double opening next_node line in site.conf example

I guess this is some copy and paste mistake which makes the example an
invalid site.conf. In my case merging the changes of the example into
our actual site.conf lead to an error because this line was merged to.

Fixes #376

Fixes #534

Fixes #487

gluon-status-page: new status page

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.

ath9k expects to get revision id 2 for the QCA9531 ver. 2 rev. 0. This
fixes the very low TX power on some devices like the TP-LINK
TL-WR841ND v10.

As ath79_soc_rev is only used to get the revision number to ath9k on the
QCA9533, just set it to the expected value on the ver. 2.

Some more cleanup.

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.

Add support for Ubiquity Air Gateway