Rename `key` to the more specific `correlation_id`
Pull up logic for routing a message to a Service

It all started as an attempt to be able to write log entries that can
be understood by humans (no more random numeric ids… or not only).
Be more explicit

We have many queues, only one queue server (per queue_service)
Document UnknownStop

Bad name, seemed funny back then
Remove options from routes

Solves issues with `{fast: true}`.
Hide the EventedWaiter

Always use ResponseStore as the public API
Pull up error handling to the common Combi::Bus
Wrap service responses to look as Deferrables

Simpler custom handling in each bus by only having to handle a single
case.
Remove some log about “deferred response”, from the specific buses
since now they all look as Deferrables.
Log service requests with their outcome and timing
Remove verboseness

Listing all remote actions every time was too much
No need for EventedWaiter