Refine the app developer dashboard (#540)

* adding refined app developer dashboard and telemetry piece

* spelling mistake

* adding kustomise telemetry

* Add a repeating row with more compact panels

also:
- consistent colours for success/error/%
- text box at top to explain dashboard & row repeating
- %ile color gradient

---------

Co-authored-by: R-Lawton <rlawton@redhat.com>

config/observability/kustomization.yaml

@@ -19,6 +19,8 @@ resources:
 # scrape config.
 # See https://github.com/prometheus-operator/prometheus-operator/issues/3071#issuecomment-763746836
   - additional-scrape-configs.yaml
+  #https://istio.io/latest/docs/reference/config/telemetry/#MetricSelector-IstioMetric
+  - telemetry.yaml
 
 patchesStrategicMerge:
   - cluster_role.yaml

config/observability/telemetry.yaml

@@ -0,0 +1,28 @@
+apiVersion: telemetry.istio.io/v1alpha1
+kind: Telemetry
+metadata:
+  name: namespace-metrics
+  namespace: istio-system
+spec:
+  metrics:
+  - providers:
+    - name: prometheus
+    overrides:
+    - match:
+        metric: REQUEST_COUNT
+      tagOverrides:
+        destination_port:
+          value: "string(destination.port)"
+        request_host:
+          value: "request.host"
+        request_url_path:
+          value: "request.url_path"
+    - match:      
+        metric: REQUEST_DURATION
+      tagOverrides:
+        destination_port:
+          value: "string(destination.port)"
+        request_host:
+          value: "request.host"
+        request_url_path:
+          value: "request.url_path"