add prometheus monitoring

apps/media/jellyfin.servicemonitor.yaml

@@ -0,0 +1,14 @@
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  name: jellyfin
+spec:
+  selector:
+    matchLabels:
+      app: jellyfin-server
+  endpoints:
+  - port: 8096
+
+# this exposes metrics on port 8096 as enabled in the jellyfin config
+# https://jellyfin.org/docs/general/networking/monitoring/
+# the metrics are available at /metrics but blocked by the ingress