Allow sending signals and receiving notifications via JMX

If jmx signalling and/or notification chanels are enabled there should be a JMX MBean exposed that will provide signalling and notification features.
There will be a method that will allow the user to send an arbitrary signal.
For the notification there will be an array/list attribute that will provide the list of notifications sent, a reset method to clean the notifications and the MBean should also emit JMX notification whenever notification is emitted