This removes RabbitMQ as well as everything else attached to it:
Erlang; the Prometheus collector; the pg-amqp-bridge and all PostgreSQL
functions and triggers; and the amqpy Python package and the Tildes code
that used it.
Note that this commit does not actually uninstall or delete any of these
packages or services, so if you have a running instance that you want to
keep (instead of re-provisioning from scratch), you will need to
manually remove them if you want them completely gone.