Respect FQDN Settings of pfSense Telegraf Plugin

[zeus86]

The Hostname of the pfSense (in terms of "how this host is Named in the DB") is currently constructed like so:
self.pfSense_host = self.pfSense_config['system']['hostname'] + "." + self.pfSense_config['system']['domain']
It takes the base hostname and appends the domainname. If you already have some basic metric collection going with pfsense and telegraf, it is plugin-configurable if either the short-hostname or the FQDN should be utilized. With the shortname (which I prefer) you'll end up with two host entries in the DB, one with and one without the Domain appended.

pfsense-to-influxdb should either respect the value as how it is configured in the pfSense telegraf-plugin or have it at least configurable throught the pfsense-to-influx-settings.

[ArmaanT]

For the sake of backward compatibility, I think making that hostname configurable with the default value being the current form would be the best option. I'd be happy to merge a PR with those changes.

[zeus86]

I think I'll do exactly this, but this will last a few days, too many other things on the todo still...