feat: add garmin postgres datasource with secret file mount

clusters/homelab/apps/monitoring/configmap-datasource-garmin.yaml

@@ -0,0 +1,21 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: grafana-datasource-garmin
+  namespace: monitoring
+  labels:
+    grafana_datasource: "1"
+data:
+  garmin-datasource.yaml: |
+    apiVersion: 1
+    datasources:
+      - name: garmin-postgres
+        type: grafana-postgresql-datasource
+        uid: bfgdydx75ju2of
+        url: garmin-db-ro.garmin.svc.cluster.local:5432
+        database: garmin
+        user: garmin
+        secureJsonData:
+          password: $__file{/etc/secrets/alertmanager-telegram/garmin_db_password}
+        jsonData:
+          sslmode: disable

clusters/homelab/apps/monitoring/helmrelease.yaml

@@ -19,6 +19,12 @@ spec:
       admin:
         existingSecret: alertmanager-telegram
         passwordKey: grafana_admin_password
+        userKey: admin-user
+      extraSecretMounts:
+        - name: alertmanager-telegram
+          secretName: alertmanager-telegram
+          mountPath: /etc/secrets/alertmanager-telegram
+          readOnly: true
       persistence:
         enabled: false
         storageClassName: longhorn