Add queues options

We already had a "queues" options starting from SlmQueue 0.3 but it was not convenient to use.

This PR wrapped the "real" options by adding a new "options" key. This will allow us to use it like this:

```php
return [
    'slm_queue' => [
       'options' => [
           'worker' => [// worker options],
           'queues' => [
               'my-queue' => [ // options ]
           ]
       ]
   ]
];
```

Usage will be obvious once I show it to you for SlmQueueBeanstalkd :)