Merge branch 'docs-aqualls-monitor-tiers' into 'master'

doc/administration/logs.md

doc/administration/monitoring/github_imports.md

...ration/monitoring/gitlab_self_monitoring_project/index.md

doc/administration/monitoring/index.md

doc/administration/monitoring/ip_whitelist.md

...nistration/monitoring/performance/gitlab_configuration.md

...istration/monitoring/performance/grafana_configuration.md

doc/administration/monitoring/performance/index.md

doc/administration/monitoring/performance/performance_bar.md

...dministration/monitoring/performance/request_profiling.md

doc/administration/monitoring/prometheus/gitlab_exporter.md

doc/administration/monitoring/prometheus/gitlab_metrics.md

doc/administration/monitoring/prometheus/index.md

doc/administration/monitoring/prometheus/node_exporter.md

...dministration/monitoring/prometheus/pgbouncer_exporter.md

...administration/monitoring/prometheus/postgres_exporter.md

doc/administration/monitoring/prometheus/redis_exporter.md

...administration/monitoring/prometheus/registry_exporter.md

doc/api/error_tracking.md

doc/api/metrics_dashboard_annotations.md