Host starts with button in ConnectionController

- Converted Event to Singleton for configuring and hosting no more than one game instance.
- Retrieve address and port from ConnectionAcceptor
- Automatically add local host to host list

#story[1010]

racevisionGame/src/main/java/visualiser/model/RaceConnection.java

@@ -15,6 +15,11 @@ public class RaceConnection {
     private final int port;
     private final StringProperty status;
 
+    /**
+     * Constructor for remote host connections.
+     * @param hostname URL for remote host
+     * @param port port for game feed
+     */
     public RaceConnection(String hostname, int port) {
         this.hostname = new SimpleStringProperty(hostname);
         this.port = port;