Adds exchange and queues to support external applications sending messages to Message Broker system.
Finish exchange settings and comments for MB_EXTERNAL_APPLICATIONS_EXCHANGE
Adjusts queue name to support general events rather than specific vote event
Adds directExternalApplicationsExchange and externalApplicationEventQueue
Adds externalApplicationUserQueue, fixes externalApplicationEventQueue binding_key
Fixed queue name to by in sync with json config file
Merge pull request #51 from DoSomething/Issue50-Add_MB_EXTERNAL_APPLICATIONS_x

Issue50 add mb external applications x