Add additional Prometheus alerts
New alerts:
- High (90%) utilization of Unicorn workers.
- Sidekiq job queueing.
- High (1%) gRPC 'ResourceExhausted' error rates.
- Postgres database deadlocks.
- Postgres database queries cancled due to deadlocks.
- Workhorse high error rates.
Closes: https://gitlab.com/gitlab-org/gitlab-ce/issues/53442 Closes: https://gitlab.com/gitlab-org/gitlab-ce/issues/45740
Edited by GitLab Release Tools Bot