Add Message count graph

[IntiGabriel]

• for each queue
• a total messages graph
• add macros to set crit and warn limits

Hi. I added some graphs for message counts. As we sometimes do not fetch all incoming messages immediately. So we can see how many messages are in the queues in a certain point in time. I also added some macros to define the limits.

[jasonmcintosh]

Thanks for the contributions!! Looks good :)