Added timeout and debugging statuses to webhooks

- Added a user-configurable timeout option to webhooks.
- Added webhook fields for last-call/error datetime, in addition to last
  error string, which are shown on  webhook edit view.

Related to #3122

resources/lang/en/common.php

@@ -74,6 +74,7 @@ return [
     'status' => 'Status',
     'status_active' => 'Active',
     'status_inactive' => 'Inactive',
+    'never' => 'Never',
 
     // Header
     'header_menu_expand' => 'Expand Header Menu',