Allow InterceptHandler to specify the messages they can intercept. This allows us to improve the performance of the broker interceptor, and will make log traces more clear.

- Add methods to return an unique identifier and the supported message types at the InterceptHandler interface.
- Include a default implementation of the new methods in the AbstractInterceptHandler. By default, all the interceptors will be able to handle any message (same as before).
- Comment verifyNoMoreInteractions() call from the BrokerInterceptorTest.testAddAndRemoveInterceptHandler(). The removeInterceptHandler() method of the broker interceptor
  polls the InterceptHandler, so an interaction will always exist after the call to onSubscribe().

broker/src/main/java/io/moquette/interception/messages/InterceptSubscribeMessage.java

@@ -6,7 +6,7 @@ import io.moquette.spi.impl.subscriptions.Subscription;
 /**
  * @author Wagner Macedo
  */
-public class InterceptSubscribeMessage {
+public class InterceptSubscribeMessage implements InterceptMessage {
     private final Subscription subscription;
     private final String username;