Added DDNS monitoring

So my WAN IP changed and I wanted to get Pushover alerts when that happens so: 

1. Go to 'Services' then 'Monit' in the OPNSense web GUI 
   

   

2. Create a new 'service test setting' that just says 'content = new'
3. Then create a new 'service setting' called DynDNS_NewIPaddress or similar 
4. Set it to 'File' monitoring with /var/log/ddclient/latest.log as file to be monitored 
5. Link the test from step 2 ( which looks for the string 'new' in the ddclient logfile ) 
6. Save the settings and check the Status page ( under the Monit menu ) 
   NOTE: Check the Log File view for errors if it doesn't save/start properly 
7. Finally test it by reloading the WAN interface under 'Interfaces' then 'Overview' 😀