(plugin) azure custom mode - add option to include premium metrics

[Sims24]

Some of the Azure Monitor metrics are only accessible when using Premium tier. Querying this kind of metrics might be a problem for those who doesn't have Premium tier enable:

{"code":"BadRequest","message":"Failed to find metric configuration for provider: Microsoft.ServiceBus, resource Type: namespaces, metric: namespacecpuusage, Valid metrics: SuccessfulRequests,ServerErrors,UserErrors,ThrottledRequests,IncomingRequests,IncomingMessages,OutgoingMessages,ActiveConnections,ConnectionsOpened,ConnectionsClosed,Size,Messages,ActiveMessages,DeadletteredMessages,ScheduledMessages,CompleteMessage,AbandonMessage,PendingCheckpointOperationCount,ServerSendLatency"}

Ref: https://docs.microsoft.com/en-us/azure/service-bus-messaging/monitor-service-bus-reference#metrics

A nice enhancement would be to add a flag to explicitly query it and then avoid error for basic tier.