gluon-client-bridge, gluon-mesh-batman-adv-core: switch roles of br-client and local-node interfaces

MAC and IP addresses are switched. This makes the gluon-client-bridge
package more useful for different routing protocols that don't need a
unique address on the client bridge.

As a side effect, gluon-radvd is now using the next-node address, which had
been considered before, but was dismissed to avoid having gluon-radvd
depend on gluon-next-node and gluon-mesh-batman-adv. This will be useful
for announcing default routes via gluon-radvd.

One downside is that this introduces a minor dependency on batman-adv in
gluon-respondd: the hotplug script that checked for the client interface
before will now check for local-node. This doesn't really matter: for mesh
protocols without a local-node interface, the check will do nothing (which
makes sense, as there is no interface to bind to for mesh-wide respondd).

gluon-announced and gluon-announce are merged to gluon-respondd.

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

All announce.d scripts have been moved to /lib/gluon/announce/announce.d
The script /lib/gluon/announce/announce.lua will collect all information
and output json.

This also fixes the type of a few fields which were strings instead of numbers.

This replaces announce.sh with a lua script of (hopefully) equal
functionality. Using lua generating JSON is much faster than jshn and
allows for greater flexibility.

+ mgmt and forward counters
+ packet in addition to byte counters for everything

* Merge gluon-alfred-ffmap into gluon-alfred
* Use gluon-crond instead of alfred's "facter" mechanism based on the broken busybox crond

This is the most basic core of the Gluon framework. Most upgrade scripts will
have to be rewritten and/or moved to other packages.