Add route to empty the task queue

[bidoubiwa]

Sometimes it might be useful to cancel the tasks queue. It happened when I send the wrong meilisearch credentials but the processes were already launched.

This is the way to do it:

    this.queue = new Queue("crawling", redis_url);
    this.queue.obliterate({ force: true });

[gmourier]

Damn, they know how to name a method; "obliterate"