Slack notification test and better documentation of customization

[adamhenson]

Summary

We support Slack notifications and threshold trigger customization. We could improve notifications with the following:

• We should create functionality to test a notification.
• We should provide better documentation about configuration.
• Instead of only allowing the configuration of thresholds - we should also allow configuration to notify when limits are exceeded... for example - a limit of performance score being 30 would notify when above.
  • Allow configuration to always notify when above the limit or only when a score changed to go above the limit.

Value

• Users will be able to confirm Slack functionality immediately.
• Explanation of configuration will prevent confusion.