Update ProtocolMetaData with Gateway IP and Port

fixes #21
When you add other Arguments to a @Observer method they work as a filter / auto injection. The method will only be called if there is a CubeConfiguration available in an active Context, and the found instance is passed in as an Argument. Conceptually the same as:

```java
@Inject
private Instance<CubeConfiguration> config;
public void startDockerImage(@Observes BeforeStart event) {
  if(config.get() == null) {
    return;
  }
}
```