Add support for WeatherGoose-II by IT-Watchdogs

Hello Observium Devs:

I was advised that if I was able to get the WeatherGoose-II working in Observium that I should create a Jira case for it to be reviewed for inclusion.

While Observium supports the newer Weathergoose devices, its support for the older unit I have was only partially successful due to lack of parsing support in discovery.  While I don't profess to be a coder, I believe I have figured out a solution that should help others that may be experiencing this issue.

ISSUE:  Observium only enumerates the ethernet interface data for a WeatherGoos-II device, does not attempt to enumerate them during discovery.

SOLUTION:

1)  Update observium/includes/definitions/os.inc.php to include the IT-WATCHDOGS-MIB as per below.  (Line 4942 is the last line in the "wxgoos" OS definition).  Without this line present, Observium will skip the php file.

$config['os'][$os]['mibs'][] = "IT-WATCHDOGS-MIB";

2) Add the attached file to observium/includes/discovery/sensors.  This tells Observium what exactly it needs to query to get both the built-in sensors and the attached temperature sensors (if installed).

I'm not the best at this, but I was able to get my WeatherGoose-II working. Please feel free to review and comment, I'd appreciate any feedback.

Thank You.

Firestorm.v1