Rework address roles, making Address::role optional, rework determining uplink/downlinks/parent/children

resources/views/status.blade.php

@@ -177,7 +177,7 @@
 												<td>{{ $o->zone->domain->name }}</td>
 												<td>
 													<a href="{{ url('system/addedit',$o->system_id) }}">{{ $o->system->name }}</a>
-													@if (($x=$o->parent()) && ($x->id !== $o->id))
+													@if (($x=$o->uplink()) && ($x->id !== $o->id))
 														<br><small>[via <a href="{{ url('system/addedit',$x->system_id) }}">{{ $x->ftn4d }}</a>]</small>
 													@endif
 												</td>