feat(metrics): collect Headscale, NetBird, Gitea and Immich metrics

gitea/k8s/ingress.yaml

@@ -7,7 +7,8 @@ spec:
   entryPoints:
     - websecure
   routes:
-    - match: Host(`gitea.forust.xyz`) || Host(`git.forust.xyz`)
+    # Metrics are scraped directly through the cluster Service.
+    - match: (Host(`gitea.forust.xyz`) || Host(`git.forust.xyz`)) && !PathPrefix(`/metrics`)
       kind: Rule
       services:
         - name: gitea-service