gluon-announced: fix help message

It incorrectly stated "-m" to be the multicast group option, when it really was "-g"

previously it was gluon-luci-privatewifi

The package luci-base now contains everything we need.

To start after haveged after the recent update.

gluon-luci-private-wifi: UI for enabling a private WLAN

This commit splits gluon-config-mode into several, mostly independent
packages.

* gluon-config-mode-core: basic functionality (required)
* gluon-config-mode-hostname: hostname field
* gluon-config-mode-autoupdater: show when autoupdater is enabled
* gluon-config-mode-mesh-vpn: fastd vpn configuration, bw limit
* gluon-config-mode-geo-location: geo coordinates
* gluon-config-mode-contact-info: contact info field

The package gluon-config-mode has been removed. You need to replace
it with these packages (or any subset of them) in site.mk:

* gluon-config-mode-hostname
* gluon-config-mode-autoupdater
* gluon-config-mode-mesh-vpn
* gluon-config-mode-geo-location
* gluon-config-mode-contact-info

Note: It is not possible to deactivate the autoupdater in config mode
anymore (expert mode will still allow it). Instead, a message is shown
in case the autoupdater is enabled.

freifunk-gluon/gluon#122

The specification says that the ifa_addr field of struct ifaddrs may be NULL,
and in Barrier Breaker, this does actually occur...

Make it clear that saving settings will reboot the device.

config-mode, mesh-vpn: refactor key generation

Previously, the config-mode was responsible for generating the fastd
secret. This patch sets the default secret to "generate" causing a
secret to be generated on its first use (e.g. show_key or start).

This also changes the info page (in Expert Mode) to show "n/a" when the
public key is not yet available.

gluon-autoupdater: unconditionally perform an update 5 minutes after boot when the whole PRIORITY delay has passed

The probability field is removed, updates are performed once per night between
04:00 and 05:00.

The crontab file was opened in write mode but in the case where no monitor is defined it would leave an empty file.

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.

This allows to use cbi-field to format plain text instead of form fields.

This package provides a secondary dnsmasq instance on port 54 which resolves
everything over the WAN interface.