Manually upload signature (#521)

* Manually upload signature

* Signature upload UI changes

* fix signature on clear

---------

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

app/Jobs/Form/StoreFormSubmissionJob.php

@@ -216,6 +216,10 @@ class StoreFormSubmissionJob implements ShouldQueue
 
     private function storeSignature(?string $value)
     {
+        if ($value && preg_match('/^[\/\w\-. ]+$/', $value)) {  // If it's filename
+            return $this->storeFile($value);
+        }
+
         if ($value == null || !isset(explode(',', $value)[1])) {
             return null;
         }