229 url for downloads (#369)

* Allow file uploads for subfleet

* Allow URL to be used for a download

* Remove old FileUploadRequest

* Move file removal logic to service layer

* Remove unused import

* Remove unused packages

app/Models/Subfleet.php

@@ -5,6 +5,7 @@ namespace App\Models;
 use App\Contracts\Model;
 use App\Models\Enums\AircraftStatus;
 use App\Models\Traits\ExpensableTrait;
+use App\Models\Traits\FilesTrait;
 
 /**
  * Class Subfleet
@@ -21,6 +22,7 @@ use App\Models\Traits\ExpensableTrait;
 class Subfleet extends Model
 {
     use ExpensableTrait;
+    use FilesTrait;
 
     public $table = 'subfleets';