Introduce guardianctrl.

Introduce guardianctrl.

guardianctrl is a small perl written CLI client to interact with
a running guardian daemon.

It supports grabbing the current status of guardian, blocking and unblocking
of addresses, sending commands for releasing all currently blocks, reloading
the configuration, regenerating the ignore list and to tell the running daemon
that the monitored files have been rotated by logrotate.

Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>