Introduction of virtual actor

A `virtual actor` will be use has a proxy to manage the interaction across region to allow players to interact with game objects across region map boundaries. This actor will fake a player in a other region and when a player interact with him, he'll proxy the message to the real actor placed in a neighbor `ActorSystem`.

We should take a look at : [Akka reliable-proxy](https://doc.akka.io/docs/akka/2.4/contrib/reliable-proxy.html)

## TODO

- [ ] Proxy the message
- [ ] Keep up to date with the position (x, y) of the real actor on the map