SimBrief integration #405 (#635)

* SimBrief integration #405

* Add briefing as API response; add acars_xml field #405

app/Http/Resources/SimBrief.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace App\Http\Resources;
+
+use Illuminate\Http\Resources\Json\Resource;
+
+/**
+ * @mixin \App\Models\SimBrief
+ */
+class SimBrief extends Resource
+{
+    public function toArray($request)
+    {
+        return [
+            'id'  => $this->id,
+            'url' => url(route('api.flights.briefing', ['id' => $this->id])),
+        ];
+    }
+}