refactor: rename k8s-manifests directory to manifests

- Rename all `k8s-manifests` subdirectories and files to `manifests`
- Update all file paths in `argocd-init.yml` to reflect the new directory name

🤖

k8s-manifests/monitoring/loki-stack.jsonnet

@@ -1,39 +0,0 @@
-local app = import "../../_templates/argocd_app.libsonnet";
-
-[
-app + {
-  name:: "loki",
-  namespace:: "metrics",
-  chart:: "loki-stack",
-  repo:: "https://grafana.github.io/helm-charts",
-  version:: "2.9.*",
-	syncOptions:: ["CreateNamespace=true", "Force=true"],
-  values:: |||
-    loki:
-      isDefault: false
-    promtail:
-      extraScrapeConfigs:
-        - job_name: journal
-          journal:
-            path: /var/log/journal
-            max_age: 12h
-            labels:
-              job: systemd-journal
-          relabel_configs:
-            - source_labels:
-                - '__journal__systemd_unit'
-              target_label: 'unit'
-            - source_labels:
-                - '__journal__hostname'
-              target_label: 'hostname'
-      extraVolumes:
-        - name: journal
-          hostPath:
-            path: /var/log/journal
-      extraVolumeMounts:
-        - name: journal
-          mountPath: /var/log/journal
-          readOnly: true
-  |||
-}
-]