Self Monitoring not deprecated functionalities

Self-monitoring was previously a category owned by devopsmonitor, it is now a deprecated category. The end-to-end flow enables GitLab admins to quickly get up and running monitoring GitLab, with GitLab.

Part of the self-monitoring capabilities are indeed deprecated and should be removed, specifically, the Self-Monitoring project. Other metrics or exporter functionality that the self-monitoring project depended on are still operational and business-critical for self-managed users and customers. Previously these capabilities were mis-categorized as self-monitoring and these capabilities need to be re-aligned to the appropriate group for ownership, maintenance and improvement.

This issue has two goals:

1. Identify all of the self-monitoring features that should remain
2. Discuss moving ownership to ~"group::application performance" or the appropriate group

List of features that need to be reclassified to be owned by ~"group::application performance"

• GitLab Prometheus Metrics
• GitLab Performance Monitoring
• GitHub Imports
• GitLab Exporter, ~"group::application performance"
• Node Exporter
• PgBouncer Exporter
• Postgres Exporter
• Performance Bar, ~"group::application performance"
• Redis Exporter
• Registry Exporter