Tests can't access management API via https

[bording]

The places we are accessing the RabbitMQ management API has http urls hard-coded, so this fails if you need to access the management API over https instead. For example, if you're trying to run tests on a CloudAMQP account.

It looks like the relevant files are https://github.com/Particular/NServiceBus.RabbitMQ/blob/develop/scripts/broker.csx and https://github.com/Particular/NServiceBus.RabbitMQ/blob/develop/src/NServiceBus.RabbitMQ.AcceptanceTests/ConfigureEndpointRabbitMQTransport.cs

[adamralph]

As @Particular/rabbitmq-transport-maintainers discussed today, we will solve this by assuming that the management API is available only via HTTPS when the connection string has UseTLS=true. This should cover virtually all cases. If the edge case ever arises that someone is not using TLS for the broker but they are using HTTPS for the API, or if someone is using TLS for the broker but using HTTP for the API, then we will cross that bridge when we come to it, but it's almost certain that this will never happen. In any case, this is only a concern when running the tests, i.e. contributing to the transport code base.