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

app/Models/Device.php

@@ -827,6 +827,11 @@ class Device extends BaseModel
         return $this->hasMany(\App\Models\MplsTunnelCHop::class, 'device_id');
     }
 
+    public function outages(): HasMany
+    {
+        return $this->hasMany(DeviceOutage::class, 'device_id');
+    }
+
     public function printerSupplies(): HasMany
     {
         return $this->hasMany(PrinterSupply::class, 'device_id');