Better Form Stats (#567)

* Better Form Stats

* fix lint

* submission timer store in localstorage

* Update test case for stats

* remove extra code

* fix form stats

* on restart remove timer

* fix resetTimer function name

* Improve form timer

* Fix timer after form validation error + polish UI

---------

Co-authored-by: Julien Nahum <julien@nahum.net>

api/app/Http/Resources/FormSubmissionResource.php

@@ -23,7 +23,8 @@ class FormSubmissionResource extends JsonResource
         }
 
         return array_merge([
-            'data' => $this->data
+            'data' => $this->data,
+            'completion_time' => $this->completion_time,
         ], ($this->publiclyAccessed) ? [] : [
             'form_id' => $this->form_id,
             'id' => $this->id