private void loadSessions() {
        ExecutorService executor = Executors.newFixedThreadPool(Math.max(8, Runtime.getRuntime().availableProcessors()),
                                                                new DaemonThreadFactory("load-sessions-"));
        loadSessions(executor);
    }
Session repository for a tenant. Stores session state in zookeeper and file system. There are two
different session types (RemoteSession and LocalSession).

@author Ulf Lilleengen
@author hmusum
configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java