gluon-mesh-batman-adv: set gateway mode to client
gluon-alfred: run every minute

The run frequency and exact time affect the alfred announce interval, so we can
just run it every minute to supply alfred with the most up-to-date data.
gluon-autoupdater: get random number from urandom

The approach with awk's rand() wasn't really random between across
devices: When srand() was called without arguments, time() was used as
seed, which of course is the same on all devices when the script is
called via cron at HH:00:00.

This patch instead uses /dev/urandom as source of random (we don't need
cryptographically strong random numbers, so urandom is just fine) but
still uses awk for the comparison as busybox's ash cannot deal with
floats in $(())