Component Importer and various Importer Fixes (#3132)

* Importer fix: we were trimming the wrong part of the classname when creating a category.  This led to categories not being recognized.

* Add a component importer.  Uses same fields as consumable importer.  Only trick: If an asset_tag is present, we checkout a component to that asset on import

Enable component importer.  Also calculate the importer classname in a cleaner fashion.

* Fix comparisons.  find can return an index of 0, which is falsy.

app/Http/Controllers/AssetsController.php

@@ -812,6 +812,9 @@ class AssetsController extends Controller
             case "consumable":
                 $redirectTo = "consumables.index";
                 break;
+            case "component":
+                $redirectTo = "components.index";
+                break;
         }
 
         if ($errors) { //Failure