Add ability to add annotations to metrics dashboard
Problem to solve
We currently do now allow users to add annotations to the charts in our metrics dashboards. This is a feature that is common in other charting tools.
Intended users
Further details
For example, on the Grafana Uptime Dashboard, there is a chart called "Overall SLA over time period - gitlab.com" where we currently cannot fully replicate because we do not have the ability to add annotations to the chart:
Based on the Slack conversation with @marin
Whenever a feature flag is being toggled via our chatops, we query the Grafana API and add the annotations. https://gitlab.com/gitlab-com/chatops/-/blob/3a0b27165e0e2d4dd8c33e6bcd32dc670d72b452/lib/chatops/commands/feature.rb#L279-285 and https://gitlab.com/gitlab-com/chatops/-/blob/3a0b27165e0e2d4dd8c33e6bcd32dc670d72b452/lib/chatops/grafana/annotate.rb for details
Proposal
- Design issue for how the annotation would look like in the chart
- Backend issue where we should probably introduce the
annotationproperty in the YAML definition - Design issue for manually configure annotation on the chart (similar to Grafana)
- Design issue on how to toggle on/off
- Multiple annotations (Future)

