Merged topic subscription search and publish into single MessagePublisher method

First step on implementing H2 storage

Minor, fixed not imported class

Cleaned MessageStore interface to avoid duplication of methods used in couple. Switched from guid + message to move messages

Separated ISubscriptionsStore from ISessionStore

Implemented H2 queue

perf/src/main/java/io/moquette/spi/impl/subscriptions/PerformanceTest.java

@@ -34,7 +34,7 @@ public final class PerformanceTest {
        cpufreq-set -g performance -u 800MHz -c 3
      */
     public static void main(String[] args) throws IOException, InterruptedException {
-        SubscriptionsStore store = new SubscriptionsStore();
+        SubscriptionsDirectory store = new SubscriptionsDirectory();
         MemoryStorageService memStore = new MemoryStorageService();
         ISessionsStore aSessionsStore = memStore.sessionsStore();
         store.init(aSessionsStore);
@@ -56,7 +56,7 @@ public final class PerformanceTest {
                             + ((i / (users * devices * values)) % subs));
 
             Subscription sub = new Subscription("CLI_ID_" + (i % users), topics[i], MqttQoS.AT_MOST_ONCE);
-            aSessionsStore.addNewSubscription(sub);
+            aSessionsStore.subscriptionStore().addNewSubscription(sub);
             store.add(sub.asClientTopicCouple());
         }