Serializer configuration support

Serailizers are no longer hardcoded into the `Serialization` class.
We are now using the correct config sections:

```javascript
akka.actor {
    serializers {
        acme = "Acme.Inc.MySerialier"
	}

    serialization-bindings {
      "Acme.My.MessageType" = acme 
    }
}
```
(do note that serializers from fallback will also be used, the same sections are used for the entire fallback chain)

Allows #308 to apply e.g. DataTableSerializer or such to a given message type
@Aaronontheweb is this the expected backoff interval?
The spec for it used the value in pigeon.config, which was 0.01s
Now that pigeon remoting config is removed, either the remote config must be changed(which I did here), or the spec for it should be changed to use the old 0.05s value in the config.