Use a single merged config file for all agents

Created by: eesaanatluri

This PR is created to use the parameter values from the newly merged single config file rabbit_config.py. This file is created as a result of our decision to merge mail_config.py with the already existing rabbit_config.py to use a single config file for all rabbitmq agents. The deploy code from PR#205 will make sure all the parameters from the mail_config are templated via vars from ansible file group_vars/all and also moved into already existing rabbit_config.py jinja template.