CAMEL-7781 - New Camel Component - PGEvent

This is a pull request for a new Camel component which will allow for the consumption of and production of asynchronous events to/from a PostgreSQL >=9.2 database by making use of the LISTEN/NOTIFY capabilities in that database. It uses the pgjdbc-ng driver to provide async notifications from the database. The code is marginally working as demonstrated in the IntegrationTest class. I hereby declare that the code contained herein is my own work and is being freely licensed under the Apache License version 2.0 and I give maintainer-ship of said code to the Apache Software Foundation.

See: #CAMEL-7781