Add ability to alert on No-Data for a specific data source at the host level.

Hello looking at this since we are having this issue today on devices. There could be situations where client asks us for a report on a device(s) and when we go to check there is just "NoData" for months and no alert b/c the device responded to other checks so considered up yet the important metrics we are supposed to be getting are no responding. How do we alert on when NoData is returned on important metric checks?

@Michael Rodrigues any progress on the "Alert Tuning" concept you mentioned? This sounds interesting.