fix monitoring of url-downloader

this is listening on 8080 but the host
has multiple IP addresses. in this case
both 208.80.154.156 and .157 are configured
on chromium.

the service (squid) for url-downloader
is just listening on .156 but the check is applied
to chromium which has address .157

so currently we get a monitoring CRIT for
being refused, because it checks the wrong IP

the check_tcp checkcommand uses $HOSTADDRESS$
so that can't be passed as an arg and is kind of harcoded

just make a new command that allows passing the IP or hostname
as an arg, but keep it associated with chromium in icinga
instead of adding some "virtual host" for the service

Change-Id: Ib58f0a41c28fc6694327fc876036bfffb38ea7d8
Merge "fix monitoring of url-downloader" into production