Notifier - move common privileged methods to a base file - AGJS-135

This is similar to what we did for DataManager,  The notifier adapters( except SimplePush ) have most of the same vars and privileged methods in the constructor. 

I've moved them out into a "base" file to get rid of the duplication.  There was one change to the name of a privileged method in the vertx adatper,  i changed the get(set)Bus to get(set)Client to be in line with the stomp and mqttws adapters.