feat(matrix): Add synapse dashboard for monitoring

apps/base/matrix/kustomization.yaml

@@ -12,3 +12,10 @@ resources:
   - ../../../shared/networkpolicies/allow-from-monitoring.yaml
 patchesStrategicMerge:
   - networkpolicy.yaml
+configMapGenerator:
+  - name: matrix-grafana-dashboards
+    files:
+      - https://git.shivering-isles.com/github-mirror/matrix-org/synapse/-/raw/v1.54.0/contrib/grafana/synapse.json
+    options:
+      labels:
+        grafana_dashboard: synapse