Change QUEUE_CONNECTION default to database (#2803)

`QUEUE_CONNECTION` is currently set to `sync` by default. We recommend
using asynchronous workers for production systems, which means that
CDash administrators have to perform unnecessary configuration right out
of the box. This PR changes the default to `database`, meaning that
asynchronous parsing is now the default behavior.

Author: williamjallen

config/queue.php

@@ -12,7 +12,7 @@
     |
     */
 
-    'default' => env('QUEUE_CONNECTION', 'sync'),
+    'default' => env('QUEUE_CONNECTION', 'database'),
 
     /*
     |--------------------------------------------------------------------------