Add Monitor stage as owner of these docs

These docs are likely owned by the Monitor team.

doc/administration/monitoring/github_imports.md

+---
+stage: Monitor
+group: APM
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
 # Monitoring GitHub imports
 
 >**Note:**

doc/administration/monitoring/gitlab_self_monitoring_project/index.md

+---
+stage: Monitor
+group: APM
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
 # GitLab self monitoring project
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/32351) in GitLab 12.7, behind a disabled feature flag (`self_monitoring_project`).

doc/administration/monitoring/index.md

+---
+stage: Monitor
+group: APM
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
 # Monitoring GitLab
 
 Explore our features to monitor your GitLab instance:

doc/administration/monitoring/ip_whitelist.md

+---
+stage: Monitor
+group: APM
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
 # IP whitelist
 
 > Introduced in GitLab 9.4.

doc/administration/monitoring/performance/gitlab_configuration.md

+---
+stage: Monitor
+group: APM
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
 # GitLab Configuration
 
 GitLab Performance Monitoring is disabled by default. To enable it and change any of its

doc/administration/monitoring/performance/grafana_configuration.md

+---
+stage: Monitor
+group: APM
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
 # Grafana Configuration
 
 [Grafana](https://grafana.com/) is a tool that allows you to visualize time

doc/administration/monitoring/performance/index.md

+---
+stage: Monitor
+group: APM
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
 # GitLab Performance Monitoring
 
 GitLab comes with its own application performance measuring system as of GitLab

doc/administration/monitoring/performance/performance_bar.md

+---
+stage: Monitor
+group: APM
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
 # Performance Bar
 
 A Performance Bar can be displayed, to dig into the performance of a page. When

doc/administration/monitoring/performance/request_profiling.md

+---
+stage: Monitor
+group: APM
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
+---
+
 # Request Profiling
 
 ## Procedure