Refactor L2 cache tenant awareness - add TenantAwareCache

The design change is to use TenantAwareCache to deal with wrap/unwrap of tenant aware keys, removing any tenant awareness from the underlying cache implementations (DefaultServerCache, redis, hazelcast etc).

ebean-test/src/test/java/org/tests/model/basic/cache/TestNatKeyCacheWithForeignKey.java

@@ -117,9 +117,9 @@ public class TestNatKeyCacheWithForeignKey extends BaseTestCase {
 
   @Test
   public void findSimple() {
-
     setupData();
     clearAllL2Cache();
+    appStats();
 
     OCachedApp app0 = findAppByName("app0");
     assertThat(app0).isNotNull();