Hooks after message is processed

Created the following hooks that are executed after the message is processed:
- on_ack
- on_timeout
- on_error
- on_reject
- on_requeue

```ruby
Sneakers.configure(hooks: { on_timeout: ->{ puts "Timeout happened" })
```
or
```ruby
class TestWorker
  include Sneakers::Worker

  from_queue 'test', hooks: { on_timeout: ->{ puts "Timeout happened" } }

  def work(msg)
  end
end
```

Any tips on how to properly test this?