Log actor failures in supervisor, see #2824

* To make it possible to override with application
  specific logging, or mute logging for certain failures
* Changed log level of Resume failures to WARNING, which
  caused all the changes to the tests

To mute default logging:

    override val supervisorStrategy = OneForOneStrategy(maxNrOfRetries = 0, loggingEnabled = false) {
      case _: IllegalArgumentException ⇒ Resume
      case _: NullPointerException     ⇒ Restart
      case _: Exception                ⇒ Escalate
    }

To add custom logging:

    override val supervisorStrategy = OneForOneStrategy(maxNrOfRetries = 0, loggingEnabled = false) {
      case _: IllegalArgumentException ⇒ Resume
      case e: NullPointerException     ⇒ 
        log.error(e, "NPE")
        Restart
      case _: Exception                ⇒ Escalate
    }


Or, for stand alone `SupervisorStrategy` classes  override `logFailure`.