(zk) Terminately immediately if zookeeper isn't found

This makes debugging easier

code/common/service/java/nu/marginalia/service/module/ServiceDiscoveryModule.java

@@ -37,6 +37,7 @@ public class ServiceDiscoveryModule extends AbstractModule {
                 See the 2024-03+ migration notes, https://docs.marginalia.nu/6_notes/6_1__migrate_2024_03_plus
                 
                 """);
+            System.exit(1);
         }
         return env;
     }