Connect to RabbitMQ first
Connect to RabbitMQ first

So that we fail fast if the RabbitMQ connection fails, for example if no
password has been specified on the CLI.

I was worried that by doing this, we risk the RabbitMQ timing out while
we retrieve URLs from the content API but Bunny, the library we're using
to connect to RabbitMQ, uses a heartbeat to keep the connection alive:
https://github.com/ruby-amqp/bunny/blob/72376c8488effc434d16accd6d5ff008b24b1720/lib/bunny/session.rb#L999

alphagov/govuk_seed_crawler