ServiceBusMessageBuilder is in wrong namespace

[fgheysels]

The ServiceBusMessageBuilder type in Arcus.Messaging.ServiceBus.Core is defined in the namespace Microsoft.Azure.ServiceBus.
This namespace is a relic from the now deprecated Microsoft.Azure.Servicebus package.
I believe the ServiceBusMessageBuilder was put in this namespace, because it formerly created instances of type Message which was in the Microsoft.Azure.ServiceBus namespace.

The Microsoft.Azure.ServiceBus package is replaced by the Azure.Messaging.ServiceBus package and the Message type is replaced by the ServiceBusMessage type.
The ServiceBusMessageBuilder namespace should be put in:
a) the Azure.Messaging.ServiceBus namespace
or
b) the Arcus.Messaging.ServiceBus namespace.

I see why we would put it in the Azure.Messaging.ServiceBus namespace though. It will be much easier discoverable, and it creates types that are in that namespace as well.

[stijnmoreels]

Ah, yes, that should be moved indeed.
Let's use Azure.Messaging.ServiceBus instead, then. 👍

Good thing we didn't released this yet 😉 .