Captive Portal: add c-wrapper captivectrl

This wrapper reads the captive settings and clients and sets the
firewall access rules. It is called every time the config changed or
everytime that a client changes. Also this wrapper is later called once
hourly to flush the chains and rebuild rules for actual clients.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
Signed-off-by: Alexander Marx <alexander.marx@ipfire.org>

config/rootfiles/common/misc-progs

@@ -1,6 +1,7 @@
 usr/local/bin/addonctrl
 #usr/local/bin/applejuicectrl
 usr/local/bin/backupctrl
+usr/local/bin/captivectrl
 #usr/local/bin/clamavctrl
 usr/local/bin/collectdctrl
 usr/local/bin/ddnsctrl