get_topic generates invalid topic names for AWS SNS

[Tehsmash]

AWS SNS topics can only have '-' and '_' in the name. https://aws.amazon.com/sns/faqs/#Features_and_functionality

The current code in BaseService and ControlPlaneServer generates topics like:

".<control plane / service name>"

replacing the '.' with an '-' works well, but then that might be incompatible with other message queues.

Perhaps passing the namespace and the service name to the "register_consumer" function on the message queue implementation would allow the different message queues to decide their own format?