Connectivity Helper to check and record device reachability (#13315)

* Fping WIP

* Update availability, move ping rrd update in the same place as db update.

* move classes around

* make device:ping command work

* use new code, remove legacy code

* save metrics boolean prevents all saves
style fixes

* update device array

* style fixes

* Update unit test

* fix whitespace

* Fix Fping stub

* fix backwards if

* fix phpstan complaining

* Fix return type

* add fillable to DeviceOutage model.

* device_outage migration to add id...

* missed line in db_schema.yaml

* 1 billion more comments on the brain damage up/down code

* tests for status and status_reason fields

* fix style again :D

* Duplicate legacy isSNMPable() functionality
but with only one snmp call ever 😎

* Remove unused variable

* fix migrations for sqlite

includes/discovery/functions.inc.php

@@ -137,9 +137,9 @@ function discover_device(&$device, $force_module = false)
     // Start counting device poll time
     echo $device['hostname'] . ' ' . $device['device_id'] . ' ' . $device['os'] . ' ';
 
-    $response = device_is_up($device, true);
+    $helper = new \LibreNMS\Polling\ConnectivityHelper(DeviceCache::getPrimary());
 
-    if ($response['status'] !== '1') {
+    if (! $helper->isUp()) {
         return false;
     }