Added instructions for changing the default rabbitmq credentials in "install-ptp-notifications." Added a note in "integrate-application-with-notification-client-sidecar" recommending that the user edit four parameters to match after they modify the rabbitmq username and password.
Story: 2011332
Task: 52123
Change-Id: Iaaa3963cc3e5f6ef099495add85e1bd8a25e94bc
Signed-off by: Matthew Montopoli <matthew.montopoli@windriver.com>