monitoring: link alerts back to grafana service dashboard
Created by: bobheadxi
Previously, alerts would only provide links to the alert solutions page. This change adds links to the appropriate service dashboard, and also updates more notifiers to leverage built-in capabilities for adding context instead of crowding the message body with links.
Closes https://github.com/sourcegraph/sourcegraph/issues/12235
Misc changes:
- add owner to notification body
- frontend page load latency may not exist
- increase alertmanager retention from 120h to 168h, since I saw this warning, likely caused by #12484:
level=warn ts=2020-07-30T03:46:10.841Z caller=main.go:437 component=configuration msg="repeat_interval is greater than the data retention period. It can lead to notifications being repeated more often than expected." repeat_interval=168h0m0s retention=120h0m0s route="{}/{level=\"warning\"}"