public AddFileInterface createFileManager(File applicationDir) {
        return new ApplicationFileManager(applicationDir, fileDirectory, configserverConfig.hostedVespa());
    }
Factory for creating providers that are used to interact with file distribution.

@author Ulf Lilleengen
configserver/src/main/java/com/yahoo/vespa/config/server/filedistribution/FileDistributionFactory.java