This plugin sends messages to a broker about events in the hub
using the proton library. This library supports the AMQP 1.0
protocol and is compatible with a wide variety of message
brokers. It queues all messages until the postCommit callback,
avoiding race conditions between message reception and database
transaction commit.
This is a different take at https://pagure.io/koji/pull-request/45
Instead of installing just the runroot builder plugin explicitly, here we
separate the plugins out into hub and builder plugins explicitly and install
each type in turn.
