Add methods for the beamline logbook

Requested by @holger.witsch and needed for the beamline logbook

The metadata manager has to implement an API to send the logs to the beamline logbook and not only the investigation logbook. The simplest is to add a set of methods:

    def notifyBeamlineInfo(self, message):                
        self.sendNotification("notification", "info", message)

    def notifyBeamlineDebug(self, message):                
        self.sendNotification("notification", "debug", message)

    def notifyBeamlineCommand(self, message):                
        self.sendNotification("notification", "commandLine", message)

    def notifyBeamlineError(self, message):                
        self.sendNotification("notification", "error", message)

    def userBeamlineComment(self, message):                
        self.sendNotification("annotation", "comment", message)