rememberingEntities with ddata mode, #22154

* one Replicator per configured role
* log LMDB directory at startup
* clarify the imporantce of the LMDB directory
* use more than one key to support many entities

akka-distributed-data/src/main/scala/akka/cluster/ddata/DurableStore.scala

@@ -115,6 +115,7 @@ final class LmdbDurableStore(config: Config) extends Actor with ActorLogging {
       case path ⇒
         new File(path)
     }
+    log.info("Using durable data in LMDB directory [{}]", dir.getCanonicalPath)
     dir.mkdirs()
     Env.create()
       .setMapSize(mapSize)