busybox: port cron to systemd

Signed-off-by: Stephan Raue <stephan@openelec.tv>
busybox: hide and deactivate syslog options and init support for now

Signed-off-by: Stephan Raue <stephan@openelec.tv>
busybox: cleanup

Signed-off-by: Stephan Raue <stephan@openelec.tv>
busybox: fix install script

Signed-off-by: Stephan Raue <stephan@openelec.tv>
busybox: remove old init system

Signed-off-by: Stephan Raue <stephan@openelec.tv>