Assetcontroller cleanup (#5858)

* Extract method/cleanup

* Remove apiStore method that is unusued since api controllers.

* Use proper model exception

* Remove old user importer.  This is now supported by the general importer framework.

* Refactor AssetsController methods.

This is a giant diff without many functional changes, mostly cosmetic.
I've pulled a number of methods out of assetscontroller, preferring
instead to create some more targetted controllers for related actions.
I think this cleans up the file some, and suggests some places for
future targetted improvement.

Fix weird missing things.

* Fix Unit test failing after date changes.

* Pass valid string to be translated.

* Some method cleanup for codacy.

* Extract trait for common checkout uses and codacy fixes.

app/Exceptions/CheckoutNotAllowed.php

@@ -5,8 +5,17 @@ namespace App\Exceptions;
 use Exception;
 class CheckoutNotAllowed extends Exception
 {
+
+    private $errorMessage;
+
+    function __construct($errorMessage = null)
+    {
+        $this->errorMessage = $errorMessage;
+
+        parent::__construct($errorMessage);
+    }
     public function __toString()
     {
-       return "A checkout is not allowed under these circumstances";
+       return is_null($this->errorMessage) ? "A checkout is not allowed under these circumstances" : $this->errorMessage;
     }
 }