Sharding Proxy fix

When shard regions are created, we can't control where they are located within a cluster. This PR adds in code to ensure that, on creation, they act as entry actor creators on nodes with `akka.cluster.roles` roles and as proxies on all other nodes.

One complication is that `application.conf` can only be read at actor creation time - otherwise the wrong `akka.cluster.roles` value is read. For this reason, `shardingProps` is defined so that it first loads the current actor system's `application.conf` file.

The `profile-link` module gets merged into the `profile` module as a result of these changes.