RabbitMQ instrumentation

[JamesNK]

There is some basic instrumentation of RabbitMQ messages. However, it is missing many of the standardized tags. And the kind is wrong in some places.

e.g.

eShop/src/EventBusRabbitMQ/RabbitMQEventBus.cs

Line 154 in 3b49f61

using var activity = _activitySource.StartActivity(activityName, ActivityKind.Client, parentContext.ActivityContext);

should be consumer instead of client. And I believe other client activities should be producer.

Conventions for spans:

• https://opentelemetry.io/docs/specs/semconv/messaging/messaging-spans/
• https://opentelemetry.io/docs/specs/semconv/messaging/rabbitmq/

Options available are:

1. Improve eshop rabbitmq instrumentation.
2. Wait for built in OTEL support in the rabbitmq library with Add OpenTelemetry support via ActivitySource rabbitmq/rabbitmq-dotnet-client#1261. Instrumentation added by eshop should be removed then.

Can do 1 and then remove with 2. Or wait for 2.