Tasks: need a way to be notified when as task fails that is external to the tasks system

[russorat]

Right now, the only way to know if a task fails is to write a custom task to see when it fails. An example can be found here: https://github.com/influxdata/community-templates/blob/master/downsampling/monitoring_task.yml#L1

But of course, if the entire tasks system is down, this task won't be run either.

As a user, i would like a way to be notified when a task fails to run that is completely independent from tasks.