* Alerting: In migration improve deduplication of title and group
This change improves alert titles generated in the legacy migration
that occur when we need to deduplicate titles. Now when duplicate
titles are detected we will first attempt to append a sequential index,
falling back to a random uid if none are unique within 10 attempts.
This should cause shorter and more easily readable deduplicated
titles in most cases.
In addition, groups are no longer deduplicated. Instead we set them
to a combination of truncated dashboard name and humanized alert
frequency. This way, alerts from the same dashboard share a group
if they have the same evaluation interval. In the event that truncation
causes overlap, it won't be a big issue as all alerts will still be in a
group with the correct evaluation interval.
Matthew Jacobson
2b51f0e263