init: disable all userland processes started from init

In order to make the system easier to understand.

These include:

* networking
* klogd and syslogd. TODO what are those for? I could not see anything useful that they do.

Also get rid of the useless S20random thing while we are at it.

rootfs_overlay/etc/init.d/S40network

@@ -1,44 +0,0 @@
-#!/bin/sh
-
-# Copied from: package/ifupdown-scripts/S40network at
-# 8ce27bb9fee80a406a4199657ef90e3c315e7457
-#
-# We then just added this line to turn it off at runtime.
-#
-# We also considered copying the file at build to / and then
-# sourcing it from S98 to be a bit DRYer, but it wouldn't work
-# very well if some S50 requires networking to work.
-#
-# This became necessary nitially when aarch64 qemu and gem5
-# started using the same Buildroot output directory.
-[ -n "$lkmc_nonet" ] && exit 0
-
-#
-# Start the network....
-#
-
-# Debian ifupdown needs the /run/network lock directory
-mkdir -p /run/network
-
-case "$1" in
-  start)
-	printf "Starting network: "
-	/sbin/ifup -a
-	[ $? = 0 ] && echo "OK" || echo "FAIL"
-	;;
-  stop)
-	printf "Stopping network: "
-	/sbin/ifdown -a
-	[ $? = 0 ] && echo "OK" || echo "FAIL"
-	;;
-  restart|reload)
-	"$0" stop
-	"$0" start
-	;;
-  *)
-	echo "Usage: $0 {start|stop|restart}"
-	exit 1
-esac
-
-exit $?
-