Refactor notifiers APIs

Actually, when a user want to add a notifier, he need to implement a notifier project, then he need to modify a jsp (notifierSelectType.jsp) and few java action classes for the recipients rendering.
I'd like to see a complete refactoring of the notifiers APIs with a notifier manager that return the role-hint of each notifiers and the name of them for the jsp, and an utility class by notifier that return a formatted string for recipients.
With that, all actions/JSPs (except specific notifier actions/JSPs like IrcProjectNotifierEditAction.java/notifierIrc.jsp) will be independant of a specific notifier and user that want to add a new notifier won't need to modify continuum files