Rewrite bundle to use adrienbrault/statsd-collector

The doc has to be updated, and I don't know if the monolog stuff still works.

btw here's what our config file now look like:

```
liuggio_stats_d_client:
    metrics_enabled: true
    metrics:
        '%liuggio_metrics_prefix%{request_method}.{request_route}.mysql.{query_table}.{query_type}': doctrine
        '%liuggio_metrics_prefix%{request_method}.{request_route}.solr.{solarium_endpoint}': solarium
        '%liuggio_metrics_prefix%{request_method}.{request_route}.exception': exception
        '%liuggio_metrics_prefix%{request_method}.{request_route}.request': increment
        '%liuggio_metrics_prefix%{request_method}.{request_route}.memory': memory
        '%liuggio_metrics_prefix%{request_method}.{request_route}.time': time
        '%liuggio_metrics_prefix%{server_hostname}.time': time
```

It is the other way around than 1.x because you can use the same collector with different metric names.