Add an alert for 0 running procfile worker processes
Add an alert for 0 running procfile worker processes

This should help guard against misconfigured CollectD proccess
plugins. Frequently the worker processes have names which don't match
the value regex, so this alert should help make this clear.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet