Captive-Portal: add crontab and cleanup scripts

The cleanup script is called every hour and deletes expired clients from
the clients file.
every night the captivectrl warpper runs once to flush the chains and
reload rules for active clients

Signed-off-by: Alexander Marx <alexander.marx@ipfire.org>

config/cron/crontab

@@ -65,6 +65,12 @@ HOME=/
 # Retry sending spooled mails regularly
 %hourly * /usr/sbin/dma -q
 
+# Cleanup captive clients
+%hourly * /usr/bin/captive-cleanup
+
+# Reload captive firewall rules
+%nightly * 23-1   /usr/local/bin/captivectrl >/dev/null
+
 # Cleanup the mail spool directory
 %weekly * * /usr/sbin/dma-cleanup-spool