Saga visualizer should point to correct NuGet based on NSB version

[DavidBoike]

When the endpoint didn't contain the saga audit plugin, this is currently displayed:

First of all, that NuGet package is deprecated. But it should look at the NServiceBus.Version header and display either ServiceControl.Plugin.Nsb4.SagaAudit or ServiceControl.Plugin.Nsb5.SagaAudit.

Additionally you could potentially fill the project name with the value of the NServiceBus.ProcessingEndpoint header, which would be correct in many cases?